Found bolt stuck inside exhaust behind prop?

[Dirkmaximus]

Hi guys,

I just bought a 16' Pontoon with a Johnson 30hp 1993. It has a 10.5x11 prop that I took off just to inspect the splines and add a little grease to them. Low and behold there was a black bolt about 1" long maybe 1/2" head or so lodged behind the prop, it was sort of stuck into the collar where the prop meets the lower unit housing. Seems it was like this for a while judging by the marks, boat runs great and didn't hear anything or see any damage, wondering if anyone had an idea where this came from, I couldn't see any missing parts anywhere, and could this possibly be the reason I could only get to 4500rpm wot? Put the boat away now so i won't know until spring. That's only judging by my on board tach, my boat tops out at about 21km/hr with 2 people on board, butterfly fully deploys!

 

[emdsapmgr]

There are two bolts that hold the carrier inside the lower unit housing in that approximate area. About the size your describe. The bolt is stainless and may have a rubber o-ring under the bolt head...

 

[Dirkmaximus]

emdsapmgr Thank you, but there was no gasket under it, it was black and showed some worn paint or "silver" underneath it. Would they be painted? Maybe I should remove the prop again and inspect closer but I was sure there were no missing bolts I could see. It was complete, not twisted or snapped off at all. What exactly is the carrier and would it be lose or in danger of breaking something should it be missing a bolt?

 

[Dirkmaximus]

The previous owner did tell me he just recently had to replace the water pump, seems legit judging by some of the scribbles in the manual, and one of the only other bolts I see on the parts list is one of the impeller housing screws. Could one of them fallen down there somehow if his mechanic wasn't careful replacing it?

 

[F_R]

If it was the one holding the carrier, it would have lost all the oil as soon as it came loose, and be a disaster by now. So that isn't it.

 

[Dirkmaximus]

Good to know! Thanks. How about the water pump screw theory?

 

[Scott Danforth]

Maybe one of the bolts holding the zinc to the bearing carrier

 

[metriccrescentwrench]

Good to know! Thanks. How about the water pump screw theory?

There shouldn't be any way for water pump hardware to get into the exhaust.

Maybe one of the bolts holding the zinc to the bearing carrier

I was wondering about that as well.

 

[emdsapmgr]

The prior owner could have dropped a water pump bolt down the exhaust when he was replacing the impeller.

 

[Dirkmaximus]

And would this prevent the engine from exeeding 4500rpm at wot?

 

[Dirkmaximus]

It was stuck in the hollow spot in the back of the prop and rotating with it

 

[racerone]

Too high a pitch on the prop will keep RPM down.---And there are other engine issues that will keep RPM down.-Not likely a wee bolt in the prop is the problem.