Lower unit damage 97 90Hp

[fishhawk16]

I'm looking at this used motor. I was told they are very good and reliable.<br /><br />However when I started to inspect the lower unit I noticed a good sized dent on the front of the gear casing. The dent is about 1/4" deep and about 1 1/2" long.<br />Both props that come with the motor have some damage, not huge amounts but looks like they both hit some rocks and need a little bit of rework. One of them has a small chunk out of it (both are aluminum).<br /><br />Should I be concerned with this type of damage? Is it possible that the shaft is bent? How can I easily check for a bent shaft. I did the spinning the prop trick but it is really difficult to tell.

 

[fishhawk16]

Re: Lower unit damage 97 90Hp

anyone?

 

[G DANE]

Re: Lower unit damage 97 90Hp

I would always be suspecious seing a dent like that. If the propshaft has a center turning mark from manufacturing, cut a piece of wood, and drive a big nail through it. Hold the wood against the antiventilating plade and bend the nail so the end will hit the propshaftcenter. Rotate prop and you will see if center moves in circles. It can not be seen on prop, as a lot of props are off center by themselves. If the lower unit isnt leaking, no water in oil, making oil creamy or milky, and everything rotates freely, dent maybe is only cosmetically.

 

[DHPMARINE]

Re: Lower unit damage 97 90Hp

True specs on prop shafts run .005 to .008.You won't see it unless you put a dial indicator on it.That said,if you don't see a wobble,put a good prop on.Any vibration?......Get it fixed.<br />DHP

 

[DHPMARINE]

Re: Lower unit damage 97 90Hp

Forgot one point.<br /><br />Why purchase a motor with known problems.A gearcase rebuild could run over $1000.00 american.<br />Lots of motors out there without visible damage.<br />DHP

 

[fishhawk16]

Re: Lower unit damage 97 90Hp

Thanks guys, I will test for a bent prop with a dial indicator. When I water tested the boat I didn't notice any vibration. We just could get the RPMs up as high as I thought for this motor. I think at WOT is was about 4500-4800 don't remember exactly. The prop has a 21" pitch.