100 Hour Two-Stroke Outboard Engine Service

boats.com Senior Editor, Lenny Rudow, joins Norfolk Marine's Chris Breeden to walk us through the 100 hour maintenance interval for your outboard engine. RELATED VIDEOS & PLAYLISTS: Boating Tips: Two-Stroke Outboard Versus Four-Stroke Outboards - https://youtu.be/Il3rm2Qr858?list=PLsiC-0C78AkEskOh3QIJAr7MOqD0D4AYr The Most Common Outboard Engine Issues: Fuel Systems and Flushing - https://youtu.be/iZeSEr1vy4Q?list=PLsiC-0C78AkEskOh3QIJAr7MOqD0D4AYr Outboard Expert: How to Check the Oil on an Outboard Outboard Engine Maintenance - https://www.youtube.com/playlist?list=PLsiC-0C78AkEskOh3QIJAr7MOqD0D4AYr Maintenance Tips: DIY Boat Repair, Updates and Improvements - https://www.youtube.com/playlist?list=PLsiC-0C78AkHQiG3YQSlbL1rcWYMGjrGJ For more how to videos, visit www.boats.com. The service bay at Norfolk Marine is headed up by Yamaha Master Tech Chris Breeden, and he shows us exactly what goes into the 100 hour service of a two-stroke outboard engine. Lenny: The 100 hour service on a two-stroke outboard is probably not something you're going to try at home. But you want to know what's going on at the dealership when they do that work, right? We're here at Norfolk Marine today, and Yamaha Master Tech Chris Breeden is going to show us step number one, of the 100 hour maintenance interval. Chris: The first thing you're going to do is drain the lower unit oil, by taking out the lower drain screw, and then you release the upper drain screw. Then you would tilt the engine down. (See our How to Change the Lower Unit Oil on a Boat video). Okay, the second step is going to be removing the spark plug boots. Then we're going to break the spark plugs loose and remove them for the compression check. When these plugs are out, now's the time to check them for how they're burning. You want the plug to be as white as possible on the center electrode. This one's in pretty good condition, this one here is starting to foul. One is pretty typical of a 100 hour service, and the other is running a little rich. Now we take the compression gauge, put it in the number-one cylinder. Make sure the safety lanyard is disconnected, so you don't make any spark as you do the compression check. Now we're ready to crank the engine over. We have 125 on that cylinder, and we have about 130 on this one. Lenny: So Chris, one was 125 and one was 130, and I know you're looking for those numbers to be close together, right? Chris: That's correct, as long as they're within 15 percent, that's acceptable. OK, now we install the new spark plugs. And, let's re-fill the lower unit. Lenny, could i get you to trim this down level so we can get the correct amount of oil in? Thank you. Now, you just pump it up until oil comes out of the top hole. You also want to clear the tip of the magnet of any metal debris before putting the screw back in. And now, we're going to grease the zerk fittings. Then we're going to remove the prop, inspect it for any fishing line, and grease it. Lenny: If anyone has any questions about how to do this, we do have a How to Change a Boat Propeller video in the boats.com video library. Now, why would you be concerned if you saw fishing line wrapped around there? Chris: Fishing line can cut into the lower unit seal and cause the seal to fail, letting water into the lower unit. Lenny: And that could cause catastrophic damage. Chris: Definitely. We also have a zinc in bad shape to replace, and we need to change the fuel-water separator in the boat.

100 Hour Two-Stroke Outboard Engine Service sentiment_very_dissatisfied 60

Boat 7 years ago 348,216 views

boats.com Senior Editor, Lenny Rudow, joins Norfolk Marine's Chris Breeden to walk us through the 100 hour maintenance interval for your outboard engine. RELATED VIDEOS & PLAYLISTS: Boating Tips: Two-Stroke Outboard Versus Four-Stroke Outboards - https://youtu.be/Il3rm2Qr858?list=PLsiC-0C78AkEskOh3QIJAr7MOqD0D4AYr The Most Common Outboard Engine Issues: Fuel Systems and Flushing - https://youtu.be/iZeSEr1vy4Q?list=PLsiC-0C78AkEskOh3QIJAr7MOqD0D4AYr Outboard Expert: How to Check the Oil on an Outboard Outboard Engine Maintenance - https://www.youtube.com/playlist?list=PLsiC-0C78AkEskOh3QIJAr7MOqD0D4AYr Maintenance Tips: DIY Boat Repair, Updates and Improvements - https://www.youtube.com/playlist?list=PLsiC-0C78AkHQiG3YQSlbL1rcWYMGjrGJ For more how to videos, visit www.boats.com. The service bay at Norfolk Marine is headed up by Yamaha Master Tech Chris Breeden, and he shows us exactly what goes into the 100 hour service of a two-stroke outboard engine. Lenny: The 100 hour service on a two-stroke outboard is probably not something you're going to try at home. But you want to know what's going on at the dealership when they do that work, right? We're here at Norfolk Marine today, and Yamaha Master Tech Chris Breeden is going to show us step number one, of the 100 hour maintenance interval. Chris: The first thing you're going to do is drain the lower unit oil, by taking out the lower drain screw, and then you release the upper drain screw. Then you would tilt the engine down. (See our How to Change the Lower Unit Oil on a Boat video). Okay, the second step is going to be removing the spark plug boots. Then we're going to break the spark plugs loose and remove them for the compression check. When these plugs are out, now's the time to check them for how they're burning. You want the plug to be as white as possible on the center electrode. This one's in pretty good condition, this one here is starting to foul. One is pretty typical of a 100 hour service, and the other is running a little rich. Now we take the compression gauge, put it in the number-one cylinder. Make sure the safety lanyard is disconnected, so you don't make any spark as you do the compression check. Now we're ready to crank the engine over. We have 125 on that cylinder, and we have about 130 on this one. Lenny: So Chris, one was 125 and one was 130, and I know you're looking for those numbers to be close together, right? Chris: That's correct, as long as they're within 15 percent, that's acceptable. OK, now we install the new spark plugs. And, let's re-fill the lower unit. Lenny, could i get you to trim this down level so we can get the correct amount of oil in? Thank you. Now, you just pump it up until oil comes out of the top hole. You also want to clear the tip of the magnet of any metal debris before putting the screw back in. And now, we're going to grease the zerk fittings. Then we're going to remove the prop, inspect it for any fishing line, and grease it. Lenny: If anyone has any questions about how to do this, we do have a How to Change a Boat Propeller video in the boats.com video library. Now, why would you be concerned if you saw fishing line wrapped around there? Chris: Fishing line can cut into the lower unit seal and cause the seal to fail, letting water into the lower unit. Lenny: And that could cause catastrophic damage. Chris: Definitely. We also have a zinc in bad shape to replace, and we need to change the fuel-water separator in the boat.

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Most popular comments
for 100 Hour Two-Stroke Outboard Engine Service

Michael
Michael - 8 months ago
I know i do all my servicing in a nice clean collared tucked in shirt.
Ryan Keys
Ryan Keys - 8 months ago
what do you grease when you pull the prop off? he says check for fishing line and grease it but never specified
tdfsu1
tdfsu1 - 9 months ago
I wouldn’t think a 100 hour service would be complete without at least inspecting the water pump impeller and housing. Sort of sloppy work to not include that step, if you ask me.
Brian Morrison
Brian Morrison - 9 months ago
What about the oil and timing belt change?
tdfsu1
tdfsu1 - 9 months ago
Brian Morrison two strokes don’t have oil and timing belts. They are lubricated through burning a fuel:gas mixture, typically 50:1 or lighter, depending if an auto lube system is installed.
bassmaster117
bassmaster117 - 1 year ago
They say you don’t wanna do it at home because they want you to take it to a shop
Al
Al - 1 year ago
Is there a specific oil you used for the lower unit oil on a 2 stroke?
Josh Glasco
Josh Glasco - 9 months ago
Al No sir all the same but there is a higher “performance” grade lower unit oil you want to use on the higher hp outboards like 50 hp+ but being a 2 stroke or 4 stroke makes no difference on your lower unit oil
mike force
mike force - 1 year ago
errr...you never said why one plugged was "starting to get fouled", nor did anything about it...
Rolling Rock
Rolling Rock - 1 year ago
Lower unit gear lube, not oil
Tom Hubba
Tom Hubba - 1 year ago
Just curious?? What would this work cost? I have the same outboard.

10. comment for 100 Hour Two-Stroke Outboard Engine Service

Tom Hubba
Tom Hubba - 1 year ago
Right in my backyard! Thanks guys!
Bill Pelosi
Bill Pelosi - 1 year ago
What's the average cost for 100 2 stroke service 1997 Yamaha V4 ????
Danny V
Danny V - 1 year ago
A heck of a lot cheaper if you do it yourself
Seth Henry
Seth Henry - 1 year ago
What’s the cost of changing out the spark plugs and the oil in the lower unit?
Shameel Ali
Shameel Ali - 1 year ago
No new spark plugs?
the roots
the roots - 1 year ago
Hi im loking for used yamaha 90 long shaft how you can help me ? Im leave at toronto. 647 863 3236
Kara Lewis
Kara Lewis - 2 years ago
Hi Mr. Lenny Rudow?My name is Kara and I have a 2001 Yamaha 25hp 4stroke F25ELHZ.It's surging at full throttle do you have any suggestions?
pineyLt
pineyLt - 2 years ago
What part of this can’t be done by the owner???
If you can’t do this I’ll bet you can’t check the oil in your car.
art gall
art gall - 2 years ago
Actually dealers do these videos half ass,just so u take it to them,when something goes wroung,advertising their shop all this is,all outboards not the same procedure.
Jesse Guy
Jesse Guy - 2 years ago
"Upper drain screw"You mean "vent"?
Richard Koldenhoven
Richard Koldenhoven - 2 years ago
1/2 ass - didn't show us the last 2 steps..plus lots more

20. comment for 100 Hour Two-Stroke Outboard Engine Service

marty pfeif
marty pfeif - 2 years ago
Can anybody tell me if you need a different size grease gun for a 2 stroke and a 4 stroke motor, or are the fittings the same size?
Brian Race
Brian Race - 2 years ago
Great video. Thank you.
Tito r
Tito r - 2 years ago
At 1:51 you mention the safety line, where's that line ? also do you have a video of how to maintain and clean carburetors, I just bought a 135 HP outboard six cylinders and I have to spray with fuel cleaner to make the motor start . Thanks
Craig Telfer
Craig Telfer - 2 years ago
safety lanyard on ignition
Gearhead Outdoors
Gearhead Outdoors - 2 years ago
I was going to leave a smart ass comment about “not doing this at home” but after reading some of the questions in the comments clearly half of this videos demographic shouldn’t be attempting repairs on anything they own...
Brad Tallman
Brad Tallman - 2 years ago
Thanks for doing the video, guys. WHAT IF... at 100 hrs...one cylinder's compression is low? What can be done? Overhaul time already?
Varnce
Varnce - 1 year ago
Brad Tallman how low? Should be within 10psi of each other. 110-120 or higher is normal.
Steve Wilson
Steve Wilson - 2 years ago
What about the impella
Varnce
Varnce - 2 years ago
Nah man they don't check that. Water circulation isn't important
Liam MG
Liam MG - 2 years ago
That’s a 100 hour service ? I’d rather drink my dollas than pay for that bullshit ! What about the water pump , fuel diafram, oil change ???
Iamadroid
Iamadroid - 2 years ago
Liam MG Its a 2stroke so the oil is changed every time you add gas!
George Mulligan
George Mulligan - 3 years ago
What a joke something you definitely do not want to tackle at home. My ten-year-old does the service on our outboards. I even have him do a pressure test to make sure the seals are okay
Hakeem Abdul Jabbar Rajput
Hakeem Abdul Jabbar Rajput - 3 years ago
like
Saltwater
Saltwater - 3 years ago
Okay seen it on all vids and understand how but the why is not connecting with me.
Why do you fill the lower unit from the bottom plug up instead of pouring it in the top until full?
Micheal Portwood
Micheal Portwood - 3 years ago
Saltwater Outdoors because if you'd tried to fill it with the bottom plug and you would get air in the system
Saltwater
Saltwater - 3 years ago
Thanks and wasnt sure how small the hole was as far as air and/or pouring it in  But make a lot of sense  what you said
boats.com
boats.com - 3 years ago
Hi, if you leave the bottom plug in and try to fill from the top, the air being displaced by the oil can't get out. And if you leave the bottom plug out and fill from the top, well, the oil just runs out. So, the only way to get the job done is to remove both plugs, and fill from the bottom.

30. comment for 100 Hour Two-Stroke Outboard Engine Service

Patrick Hascall
Patrick Hascall - 3 years ago
Nice video, but far from complete. It is critical to decarbonize the engine with combustion chamber spray such as OMC Engine Tuner every 100 hours or once a year. Carbon build up on piston rings "will" eventually cause engine damage and needs to be cleaned as before mentioned. Spark plugs do fail and should be "replaced" and not just inspected every 100 hours. The timing and carburetor sync should be checked and adjusted. Water pump impeller should be inspected and replaced as needed. Engine needs to be checked for proper operating temp (a cold running engine, as well as a hot one, will cause engine damage over time). Cylinder head bolts should be checked and set to proper torque specs. Electrical connections should be inspected for corrosion and properly lubed and/or sealed. Wiring should be inspected for wear and brittleness and repair or replaced as needed Engine fuel filter should be inspected, cleaned and/or replaced, not just the water sep filter. All fuel connections should be inspected for leaks and hoses need to be inspected to make sure they are not getting hard and brittle, and should be replaced as needed. Powerhead should be recoated with an anti-corrosion lube. I actually use gun oil on all my customers engines, and as I live and work in the high salt environment of Hawaii, and corrosion is a big issue. I have tested many lubes and several are good, but try and avoid lube sprays that leave a thick, sticky coating. Mechanics hate it, and it also attracts grime and retains heat. Been repairing outboards for over 30 years, and everything mentioned is absolutely needed to ensure proper operation, performance and engine life.
Kevin HeyMan
Kevin HeyMan - 2 years ago
@Richard Koldenhoven
You can't. Thankfully, they're simple
Richard Koldenhoven
Richard Koldenhoven - 2 years ago
how do you clean carb without taking it apart?
Bob Saget
Bob Saget - 2 years ago
Patrick Hascall where are you from
Patrick Hascall
Patrick Hascall - 3 years ago
And oh yes... vacuum and pressure test the lower unit. I also include a carburetor cleaning on smaller outboards, as many are not run with water sep. filters or have built in tanks which do get dirty and the carbs do pick up water and junk from tank. Out here, it is next stop Tahiti if your engine fails, and I pride myself on "never" having had a customers engine fail due to improper service.
Farmer2492
Farmer2492 - 3 years ago
just watched this again fantastic very informative how would i get the paint code for my outboard Thank you
Joe M
Joe M - 3 years ago
Great video. Thank you for sharing!!!
Del Bryan
Del Bryan - 3 years ago
Hello great video I have 5 hp mercury 2 stroke outboard Motor prop Propeller I was wondering about the seal in mine motor have not see the water in about 15 years what should I be looking for
boats.com
boats.com - 3 years ago
Hey Del - ouch - after 15 years out of the water, you have to expect to replace every seal, gasket, fluid, and non-metallic part (IE the water pump impeller). That's just too long for an outboard to sit.
blake the snake
blake the snake - 4 years ago
Excellent video. To the point no bs. Thanks for this
Farmer2492
Farmer2492 - 4 years ago
Hi Fantastic video, i have a Yamaha 30 HP and a 50 HP about 90 models what gearbox oil should i use.
Farmer2492
Farmer2492 - 4 years ago
Thank you
boats.com
boats.com - 4 years ago
Hey Farmer 2492 - for both the 30 and the 50, Yamaha recommends Hypoid SAE#90 gear oil.
TheCameraman14
TheCameraman14 - 4 years ago
What type of oil is used in the lower unit?
Jerry
Jerry - 1 year ago
Antifreeze
Varnce
Varnce - 1 year ago
WD40
sue W
sue W - 3 years ago
Change oil in 4 stroke Honda outboard
boats.com
boats.com - 4 years ago
Hey Cameraman14 - that depends on the make and model of your outboard. Some use Hypoid high-viscosity, some others specify by brand (such as Quicksilver High Performance Gear Lube for some Mercury motors) and some others can use generic lower unit gear lube. Refer to your owner's manual or do a bit of Googling, to find out the specifics about your outboard before changing the lower unit oil..
skankhunt42
skankhunt42 - 4 years ago
so in the beginning the dude said to not do this maintenance at home but take it to a dealer dealer? WTF. Everything performed in this video can be easily done at home for next to nothing and needs to be done every season or 100 hours which ever comes first.
Melinda Todd
Melinda Todd - 4 years ago
i have a mercury 70hp outboard motor and when i pump the fuel to the motor when the ball gets hard the fuel pisses out of what looks like the carb...any help is appreciated thxs
Melinda Todd
Melinda Todd - 4 years ago
thanks
Anthony Agostino
Anthony Agostino - 4 years ago
that happens if you overpump. it pissess out so not to flood or liquid lock engine if you forces it through somehow if you manage to get a liquid in an engine when you start it it does not compress and would lock you up or bend a rod
Muscle man
Muscle man - 4 years ago
I can do this in 15 mins max, i would charge just 30 bucks oil included.
Jonah Boudreaux
Jonah Boudreaux - 1 year ago
Y’all on crack thinking this service is 15-30$ they prolly charge or charged the man close to $200
Muscle man
Muscle man - 4 years ago
@Ad Vic ha i can get a get a gallon of oil for 20 bucks, and did i say plugs included, and a i would use a tube of grease after sevicing 50 outboards or more, im not going to use a whole tube to lubricate screws. All in all i would make anywere from 15 to 20 dollars for a simple job.
Adam's Aquatics
Adam's Aquatics - 4 years ago
+Required Shrimp0 idiot.........the oil is $13 a quart, need at least 2, grease is $9 a tube, only need 1, plugs are $4 a piece.........
Tom Nguyen
Tom Nguyen - 4 years ago
Hey, I have a question for you guys. My boat motor is not pumping water. I opened up the lower unit and checked the impeller, but it was in good condition. Any thoughts about this??
And also, the little inlet beneath the impeller, is it supposed to be closed or open, because mine seems to have something blocking it.
Thanks
Muscle man
Muscle man - 4 years ago
Ha what a pain in tha butt!
Farmer2492
Farmer2492 - 4 years ago
my brother inlaw brought an outboard once wasn't pumping water man put a new impeller in i checked it he left the pin that holds the impeller on the shaft off
Muscle man
Muscle man - 4 years ago
check the part that spits out water for clogging, you can poke it with a wire.
boats.com
boats.com - 4 years ago
Hey +Tom Nguyen, if you see any blockages, obviously, you should clean them out. That said, once you've dropped the lower unit it makes sense to do a complete water pump rebuild even if the impeller itself looks fine.
local7777
local7777 - 5 years ago
Spark plugs "As white as possible"?
I thought white plugs mean a lean mixture condition, which can result with severe motor damage. Spark plugs should have a light brown color.
Andrew Freeman
Andrew Freeman - 2 years ago
Yes he said ceramic center piece, but he should just say light brown in color, not white or black..
Richard Koldenhoven
Richard Koldenhoven - 2 years ago
I think he meant the ceramic piece - I hope..
Richard Wilson
Richard Wilson - 5 years ago
I HAVE 1989 45 HP MARINER MOTER WILL NOT RUN FAST ON THE LAKE IT TROLLS FINE . I REBUILT THE FUEL PUMP CHANGED THE FILTER. WHAT SHOULD I TRY NEXT
Dream Love
Dream Love - 5 years ago
Where can i buy one of those compression checkers????
Varnce
Varnce - 2 years ago
You're* spelling it wrong
Dream Love
Dream Love - 5 years ago
Thank you! :)
donadthegonad
donadthegonad - 5 years ago
"...greeze the zirkfittens..." ??
darren loud
darren loud - 6 years ago
Also good idea to inspect the impeller
Bill Smith
Bill Smith - 6 years ago
Thanks guys for the good information.
Bill
manuel ferrera
manuel ferrera - 6 years ago
Hi... is it normal for the spark plugs to have oil on them?? I noticed mine did
boats.com
boats.com - 6 years ago
Hi @manuel ferrera. It's not uncommon to see a sheen on the plugs in a two-stroke, but they shouldn't be coated or caked with black goop. If they are, you need to check the fuel-oil mixture and make sure the fuel isn't being over-oiled. 
Gary Phillips
Gary Phillips - 6 years ago
"You probably won't be doing this at home." Why not? It's all simple.
Richard Koldenhoven
Richard Koldenhoven - 2 years ago
thats a bingo.. "inglorious bastards"
Nemo
Nemo - 2 years ago
Because they're a boat dealer and if you do this work yourself they make less money.
michael walker
michael walker - 7 years ago
how do you care for a outboard motor when you have a disability and I want to learn more about it from Michael walker keen old salty boat owner

50. comment for 100 Hour Two-Stroke Outboard Engine Service

THEMOWERMEDIC1
THEMOWERMEDIC1 - 7 years ago
I always include a lower unit pressure and vac test.
THEMOWERMEDIC1
THEMOWERMEDIC1 - 7 years ago
I always include a lower unit
BassinWithBuck
BassinWithBuck - 7 years ago
I tend to do the impeller every two years on an 85 Mercury XR2.....should I do her every year to be safe? Motor runs like a champ and want to keep it that way.
MrSupermugen
MrSupermugen - 1 year ago
5 years ago but, We do our impellers, plugs, gearbox oil and tilt fluid.. every year. we also check for fishing line, cracks in hoses and grease steering and linkages often.

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