Yammy 115 Timing Belt

[captpierre]

Looked in owners manual of my 10 yr old Yammy.

Says timing belt should be replaced after 5 yrs.

Haven't done it yet.

I do my own regular end of season maintenance. Runs perfectly.

I guess I should get that done. ???

I did change plugs and impeller at 5 yrs.

Edited October 9, 2017 by captpierre

[ecmilley]

Yes get it done and pretty simple as far as timing belts go

[Mister G]

I don't know anything about Yammy's but if it's a interference motor and that belt breaks while running you now have a nice heavy anchor because the valves will be driven into the pistons. NOT GOOD....

[16 Footer]

Why does your Yammy have a timing belt when a timing chain would last the life of the engine?

Like car engines the timing belt is an unnecessary expensive repair when timing chains last the life of the engine.

[DRIFTER_016]

Why does your Yammy have a timing belt when a timing chain would last the life of the engine?

Like car engines the timing belt is an unnecessary expensive repair when timing chains last the life of the engine.

 

Another reason to love my 115 Merc!!!

It has a chain.

[OhioFisherman]

Why does your Yammy have a timing belt when a timing chain would last the life of the engine?

Like car engines the timing belt is an unnecessary expensive repair when timing chains last the life of the engine.

 

I bought a used Chevy Chevette years ago, I had it about 8 years and had to replace the timing belt twice. I replaced them myself and thought it was pretty easy compared to replacing a timing chain. You are right though most timing chains never need to be replaced.

[Old Ironmaker]

My 115 Mariner has a chain, it is a Yamaha/Merc hybrid. I suggest you go to iboats.com, join at zero charge and you have thousands of years experience at your finger tips. If the folks there don't have the right answer the near does not excist.

[Mister G]

Why does your Yammy have a timing belt when a timing chain would last the life of the engine?

Like car engines the timing belt is an unnecessary expensive repair when timing chains last the life of the engine.

Because timing belts are more precise then a chain that can stretch. Many fine tuned foreign car engines have belts rather then chains. Lexus has a 4.7L engine that has a timing belt while a Ford Tempo only uses chains.

 

Five years seems like a short duration for a outboard engine to have to change the timing belt. Most car/truck engines suggest the belt to be changed at about 145000 km.

 

This could be why Yammies run so much better then those ugly black anchors you always see on cheap boats....LOL

[Fisherman]

Because timing belts are more precise then a chain that can stretch. Many fine tuned foreign car engines have belts rather then chains. Lexus has a 4.7L engine that has a timing belt while a Ford Tempo only uses chains.

 

Five years seems like a short duration for a outboard engine to have to change the timing belt. Most car/truck engines suggest the belt to be changed at about 145000 km.

 

This could be why Yammies run so much better then those ugly black anchors you always see on cheap boats....LOL

[Old Ironmaker]

Another reason to love my 115 Merc!!![

It has a chain.

Dave, depending on the year your Merc there is a good chance the main components of your Merc is actually a Yamaha/Merc hybrid. My 115 HP Mariner is a Merc/Yamaha hybrid. As is my 15HP Merc kicker. Edited October 10, 2017 by Old Ironmaker

[DanD]

If a manufacturer is trying to squeeze out as much HP, at the most cost effective way; a timing belt will win out every time.

I'm not saying its the best thing to ever happen in engine design; but it works well in so many ways.

The biggest thing to the manufacturer is the cost to produce a belt driven cam, rather then a chain driven. The next thing is weight 5-6 lbs of chain, compared to maybe a few ounces of a belt. Right there a belt is free HP; easier to spin something light.

The only downfall is the service intervals of a belt.

 

Dan.

[bigbuck]

Belts run quieter and smoother than timing chains. Get it done, yammies are typically interference engines.

[DRIFTER_016]

Dave, depending on the year your Merc there is a good chance the main components of your Merc is actually a Yamaha/Merc hybrid. My 115 HP Mariner is a Merc/Yamaha hybrid. As is my 15HP Merc kicker.

 

 

OI, mine is a 2013 4 stroke.

[2 tone z71]

Didn't know Mariner made a 4 stroke hmmm

 

After thousands of hours and lots of service I think my 60 yamaha is on its last troll,I'm hoping it gets me thru the 2018 season although it don't owe me a cent.

Edited October 11, 2017 by North East Shark

[Old Ironmaker]

Why does your Yammy have a timing belt when a timing chain would last the life of the engine?

Like car engines the timing belt is an unnecessary expensive repair when timing chains last the life of the engine.

That is if the timing chain wasn't on any of Mercedes gas engines of the early 80's. I had a chain go on my 5.6 liter V8 and it required an engine rebuild to the tune of $3500.00, in 88', ouch. Not 20,000 KM later the exact same thing happened so I took it to a Benz dealer and they did the rebuild and put in what they called a "double" timing chain. Is there such a thing? No cost to me. As for the first rebuild they said I should have gone to them first. Another expensive life lesson.

Edited October 11, 2017 by Old Ironmaker

[DRIFTER_016]

I took it to a Benz dealer and they did the rebuild and put in what they called a "double" timing chain. Is there such a thing?

 

 

Yes, it's called a double roller timing chain.

They have less stretch and are used mainly in performance applications.

 

http://www.onallcylinders.com/2013/07/26/standard-vs-roller-timing-chains/

[KawarthaAngler]

I never knew this had to be done.

 

I have a 2007 75hp Honda and a quick Google search showed me a Youtube video of a guy changing the timing belt on the 90hp version of my motor. Looks like I'll be looking into this more ASAP!

 

Thanks!

[Old Ironmaker]

Belts run quieter and smoother than timing chains. Get it done, yammies are typically interference engines.

May I ask what is an "interference chain?"

[DRIFTER_016]

May I ask what is an "interference chain?"

 

 

Interference engine not chain.

 

Save's me the trouble of writing it out.

 

https://en.wikipedia.org/wiki/Interference_engine

[moemoe]

I have a 225hp yammy and thought same issue after 5 years, took it to bay city marine who i trust and have had good service, they said only replace of necessary and if not cracked or loose like the majority are save your money and dont replace

[BillM]

My buddy is a mechanic for the Coast Guard, said the same thing. Do a visual, if it's fine there's no need to touch it. It's not like it's got a tensioner or rollers like a car has (Which is usually the part that fails and takes the engine with it) timing belts rarely if ever just snap.

[DRIFTER_016]

My buddy is a mechanic for the Coast Guard, said the same thing. Do a visual, if it's fine there's no need to touch it. It's not like it's got a tensioner or rollers like a car has (Which is usually the part that fails and takes the engine with it) timing belts rarely if ever just snap.

 

 

Unless it's in my buddies wife's 1 year old Subaru Outback.

Sitting at a light waiting to turn left. Pop!!!

Engine toast!!!

[DanD]

I have a 225hp yammy and thought same issue after 5 years, took it to bay city marine who i trust and have had good service, they said only replace of necessary and if not cracked or loose like the majority are save your money and dont replace

 

I'm sorry here guys but that's not the best advice.

If the manufacturer says replace it; it would be foolish not to listen.

 

My buddy is a mechanic for the Coast Guard, said the same thing. Do a visual, if it's fine there's no need to touch it. It's not like it's got a tensioner or rollers like a car has (Which is usually the part that fails and takes the engine with it) timing belts rarely if ever just snap.

 

Oh yes it does have a tensioner.

 

https://www.amazon.com/Tensioner-Timing-Belt-Yamaha-75-115hp/dp/B01LXNR5IR/ref=pd_sim_263_1?_encoding=UTF8&psc=1&refRID=W89TESZJGFDY6EXRGP9J&dpID=31yS71D28IL&preST=_SY300_QL70_&dpSrc=detail

 

Like the old Fram filter commercial "you can pay me now or you can pay me later" and it's not just the cost of a belt change or the damage to the engine if it breaks. Its you being out on the lake (the opposite end of where you launched) and the belt decides to let go. A timing belt is a glorified rubber band; like anything made of rubber, it never stops curing getting dryer and rotting. Usually a timing belt doesn't break in two; but one of the teeth will rip off and like dominoes will rip off a number more. That bald spot on the belt comes to the small gear on the crankshaft and the cam(s) stop rotating. Crank has enough inertia that it'll make two or three more rotations. That's when the pistons come up and kiss any open valves.

So go ahead and throw the dice and not replace the belt; I've seen SOME people win at craps.

One last thing.

If you guys think the cost is to much for this, wait till we follow suit with some European counties. 5 years old tires, regardless of remaining tread; must come off the road. For the exact reason as a stated above; rubber never stops curing.

 

Dan.

[Mister G]

 

I'm sorry here guys but that's not the best advice.

If the manufacturer says replace it; it would be foolish not to listen.

 

 

Oh yes it does have a tensioner.

 

https://www.amazon.com/Tensioner-Timing-Belt-Yamaha-75-115hp/dp/B01LXNR5IR/ref=pd_sim_263_1?_encoding=UTF8&psc=1&refRID=W89TESZJGFDY6EXRGP9J&dpID=31yS71D28IL&preST=_SY300_QL70_&dpSrc=detail

 

Like the old Fram filter commercial "you can pay me now or you can pay me later" and it's not just the cost of a belt change or the damage to the engine if it breaks. Its you being out on the lake (the opposite end of where you launched) and the belt decides to let go. A timing belt is a glorified rubber band; like anything made of rubber, it never stops curing getting dryer and rotting. Usually a timing belt doesn't break in two; but one of the teeth will rip off and like dominoes will rip off a number more. That bald spot on the belt comes to the small gear on the crankshaft and the cam(s) stop rotating. Crank has enough inertia that it'll make two or three more rotations. That's when the pistons come up and kiss any open valves.

So go ahead and throw the dice and not replace the belt; I've seen SOME people win at craps.

One last thing.

If you guys think the cost is to much for this, wait till we follow suit with some European counties. 5 years old tires, regardless of remaining tread; must come off the road. For the exact reason as a stated above; rubber never stops curing.

 

Dan.

Good advice, but as I said once before 5 years seems like a very short time for a timing belt.....do you know why ? ? ?

 

And the Europeans don't know nothing about tires . . . . LOL

[DanD]

Good advice, but as I said once before 5 years seems like a very short time for a timing belt.....do you know why ? ? ?

 

And the Europeans don't know nothing about tires . . . . LOL

 

A car's engine on average, is likely only using 30 - 40% of available power. It's not to often you'll need/want to do a full throttle take off. Unless you're 16 and dad can't see you. LOL

So yeah automotive manufacturers measures belt change intervals in mileage (approx 160K Klms) rather then time.

Boat motor is likely using 80 - 90% of its power most times. We've all likely done this; at the end of a drift, we start the motor; barely let go of the key and we nail the throttle. Running half or better throttle in a chop and the prop comes out of the water. The tachometer pegs its needle; then the next second the prop is back in the water and drags the rpm down just as fast as they went up.

In other words we beat the living crap out of boat motors. I'm surprised at how well they handle these beatings. So the harder we treat/beat on engines/motors the more frequent the service intervals.

 

Dan.