Prop shaft

[Dwalker78]

Can a bent prop shaft cause damage to the crank shaft and bearings

[Sequoiha]

depends on how bad it is bent and how long you run it,, the excess vibration cant be good for it..

[Dwalker78]

I hit something 40 miles off shore and leaked all the oil out of the foot and did not know any of till the overheat alarms went off mechanic said I need a lower unit and a short block does this sound right insurance company is trying to say that me hitting something could not have cause damage to the short block I just want some more opinions because I know nothing about a boat motor I have them serviced regular it is a yamaha 150 four stroke with 1300 hrs

[99yam40]

hitting something is an insurance claim,
but running motor until it overheats till it is harmed is not

[Dwalker78]

I agree but did not know that I hit something till the overheat alarm went off we was running in some ruff seas and the water pump never stopped peeing water we cranked it back up when we got to the marina and it still was pumping water and the oil level was good we cut the motor off when the alarm went off and come back on one engine did not realize that the shaft was bent until we pulled the boat out of the water and oil was running out around the prop and my mechanic advised that I may want to call my insurance agent 1st claim in over 20 years paid in probably 10 times what the claim is

[Sequoiha]

If your prop shaft is bent enough for the gear lube to come out, you would have known this, it would have vibrated your teeth out.. there is no missing a bent prop shaft... and a bent prop shaft will not cause a over heat alarm, seems to me you have something else going on.. Did your mechanic tear down the block, for what reason does it need to be replaced... I have seen an impact twist the drive shaft, but it usually doesnt bother the crank.. and again if you hit something hard enough for this to happen you would have known it...

[Dwalker78]

He tore it down what else would have caused it to over heat if the water pump is working and the oil is good also lost compression in one cylinder

[99yam40]

Not enough info to say what the real problem is.


you will have to have mechanic that tore it down tell you how he thinks a bent prop shaft would cause you to loose compression on one cylinder and what damage was done to that cylinder.


Apparently we are not getting the whole story
Does not make any sense to me

[99yam40]

also lost compression in one cylinder

broke or stuck rings, burnt or stuck valve, hole in piston, are some things and I am sure there are others

[Oceannavagator]

Your water pump will fail when the bearings in the lower unit fail. Bearing failure causes seal failure and it's easier for the pump to put water through the lower unit than to pump it up to the engine. This forces oil out of the gear box and makes everything worse. The fact that you were probably running hard means that the engine needed more water for cooling and didn't get it.
If I was dealing with your ins agent I'd just insist that it was the result of an accident and give no ground. In the end it will be his or his boss's call.

[Dwalker78]

The bad thing is I my motor never stopped peeing water not sure if that means anything hard to type all of the stuff that went on if anybody is up willing to let me call and talk to them you can pm me all I want is a honest mechanics opinion I trust my mechanic but my insurance adjuster is trying to act like a 50 mechanic and I want more than one mechanics opinion

[Sequoiha]

I emailed you my number,, be glad to talk to you...

[Dwalker78]

Thanks i will call you on Monday