Anyone have a Yamaha tech?

[Oscar162]

My 05' Yamaha 250 suddenly lost power and developed a top end knock. I do all my own maintenance and minor repairs... but know enough to know when I'm over my head. Gut tells me a bearing? It mostly just sounds expensive. Anyone have "a guy"?.... All the local Yamaha dealers I've reached out to locally are swamped - earliest I can get it in is July 13th at Lordship. Located in the lower mainland. Cheers

 

[Pineapple Express]

Sending you a PM...

 

[kingblazer84]

My 05' Yamaha 250 suddenly lost power and developed a top end knock. I do all my own maintenance and minor repairs... but know enough to know when I'm over my head. Gut tells me a bearing? It mostly just sounds expensive. Anyone have "a guy"?.... All the local Yamaha dealers I've reached out to locally are swamped - earliest I can get it in is July 13th at Lordship. Located in the lower mainland. Cheers

sounds like you spun a bearing, does it get rotationally louder as you go up in rpm? rod knock or bottom end crank bearing failure I would check the oil for sparkles good indication of bearing material contamination.

 

[Oscar162]

sounds like you spun a bearing, does it get rotationally louder as you go up in rpm? rod knock or bottom end crank bearing failure I would check the oil for sparkles good indication of bearing material contamination.

Thanks for that.... same noise at higher RPM yes. Shut it down immediately and limped home on the kicker... hopefully helped the outcome. Compression is good in all cylinders - oil appears ok, but want to leave the drain for whoever helps me out with the repair.

 

[chinnok]

Repairs | Seaboardmarine

Seaboard Marine is primarily a repair service to conventional propulsion systems. Consulting is another service we offer to help the purchase of new/used boat as well as upgrade vessels.

www.seaboardmarineservices.com

Try this guy, probably busy but he's one of the best. Mobile too!!

 

[ship happens]

Honestly don't know how an engine like that can spin a bearing. Those are bushing type bearings that are pin locked. Either way not happening. Even if the thing broke free you would have a lot more problems then just a noise.

I would honestly look at the tensioner and belt first. Then gearcase.

 

[Oscar162]

Honestly don't know how an engine like that can spin a bearing. Those are bushing type bearings that are pin locked. Either way not happening. Even if the thing broke free you would have a lot more problems then just a noise.

I would honestly look at the tensioner and belt first. Then gearcase.

I’ve had a good look for anything obvious ( I’m by no means a tech) and can’t diagnose. Compression test good and oil appears ok on the stick - will leave the drain to whoever ends up helping me out. Holding a stethoscope to the power head it seams to be a knock at the top… under flywheel. Pretty confident it isn’t lower unit.

 

[ship happens]

I don't know how many times there has been a boat at my shop with "engine knock" and turned out to be the lower unit. It echos through the exhaust housing and through the crankshaft. Seen it more than a couple dozen times. Just saying its a possibility

 

[Oscar162]

I don't know how many times there has been a boat at my shop with "engine knock" and turned out to be the lower unit. It echos through the exhaust housing and through the crankshaft. Seen it more than a couple dozen times. Just saying its a possibility

Thanks for that… I’ll have a closer look.

 

[ship happens]

Any filings in the gear oil?

 

[Fisher Down]

Several people have suggested it may be your lower unit...

Does you issue only happen in gear, in neutral, or does it matter? This may direct you 'where' to look further.

FD

 

[profisher]

Outfitters years ago had an engine with a loud knock that sounded like engine..turned out to be gearcase. Spin the prop by hand and see if you get any noise. You could drop the gearcase and run it for a few seconds without it on there to isolate it either way.

 

[ship happens]

Usually 9 times out of 10 when it's the lower unit, it's always the pinion missing a tooth or 2 or 3 etc.

 

[Oscar162]

Thanks for the input and all of the PM's. Lucky enough to nail down Ryan Neff, I was dreading having to deal with a dealership. Sounds like thrust bearing failure as there is play in the flywheel, and the knock is still present when the LU is removed. Ryan may have a short block that will work... fingers crossed. Unsure of the cause... came on suddenly with no warning, and I'm extremely vigilant with maintenance. Look forward to hearing his findings when it's apart, may proceed with an ins claim - bit of a shot in the dark but nothing ventured.....nothing gained. Cheers.