Burning rubber smell no smoke

[Gavman04]

Greetings all,

I just bought a 82' starcraft with an 82' 140 mercruiser inboard in October. I'm in Alabama and had it stored from November-January I took her out last weekend and she went for 2 hours and no problems until after 5 minutes of full throttle (I know now, that this was a mistake- won't happen again) I started smelling burning rubber (no smoke) I slowed down to 1/2 and everything was good again. I checked the belt and it "looked" fine while it was running and then again when I had it back on the trailer. (my new belt should be here tomorrow though anyway) Yesterday I took her out again and after 5 minutes of full throttle the boat jerked and then smelled of burning rubber (still no smoke) and wouldn't go its normal speed. I put it to about 1/4 throttle and it chugged along but anytime I would increase the speed anywhere past 1/2 it would slowly start to smell the reps would go up and then slow down on its own I didn't notice the temp increase at all. I checked the spark plugs and this is the picture of what all 4 look like. It starts up just fine and the engine didn't ever shut off by itself. I'm a newbie so any advice is appreciated. and if any more elaboration is needed on my part I'll respond as quickly as I can. yes- I should have taken it to a certified mechanic before buying, i bought it from my brother in law, lesson learned.

Thanks to anyone who can help!
Gavin

 

[Bondo]

and then smelled of burning rubber (still no smoke) and wouldn't go its normal speed. I put it to about 1/4 throttle and it chugged along but anytime I would increase the speed anywhere past 1/2 it would slowly start to smell the reps would go up and then slow down on its own

Ayuh,..... Welcome Aboard,.... That quote sure sounds like the rubber coupler mounted to the crankshaft that the drive connects to, is Failing,....

'n those spark plugs are waayyy past due for a change,....
My 1st choice would be AC Delco, MR43T plugs,...

 

[Scott Danforth]

Welcome aboard

with any new to you boat, you need to do all the maintenance, and replace things like the impeller, etc. you also need to pull the drive, replace the bellows, check the gimbal bearing and u-joints as well as check alignment

by the sounds of it, you will be pulling the motor to change the coupler. however it could simply be the exhaust hose melting to from lack of water flow. back to the maintenance and replacement thing.

by the way, nothing wrong for cruising along 5 minutes at WOT. I generally tool along at WOT for at least 20-30 minutes if I need to get somewhere.

 

[Rick Stephens]

Gavman,

Congratulations on the new to you boat. That Mercruiser setup is pretty easy to work on, as far as boats go, but as stated, you need to go through pretty much everything before running it again. Pull the drive, drain and split the cases, inspect and replace the water pump impeller. Personally I'd reassemble and pressure test the drive before refilling with lube, to be sure it has no leaks. Inspect and replace as needed u-joints, gimbal bearing, bellows and lower shift cable. Do engine maintenance - points and condenser cap rotor and plugs. Maybe wires. Make sure the shift interrupt works properly. Check the oil in the hydraulic pump and clean replace as indicated.

Since you look to need to pull the motor and replace the coupler, great time to inspect the shutter in the exhaust and the exhaust manifold itself. Rotten old exhaust manifolds cause more problems than almost anything else. And while the motor is out carefully inspect the transom. A rotten waterlogged transom is second only to rotten stringers on the PITA scale.

New old boats need a thorough going over. This forum is the place to work it all out before you get out on the water and have to walk back.

Rick

 

[Gavman04]

One thing I did forget to mention is that when I pulled the drain plug on the boat there looked to be either a small amount of gas or oil in the water that came out of the drain plug hole. the water was a rainbowish color.

 

[alldodge]

One thing I did forget to mention is that when I pulled the drain plug on the boat there looked to be either a small amount of gas or oil in the water that came out of the drain plug hole. the water was a rainbowish color.

As others mentioned its your engine coupler. When the rubber burns it melts a bit and the oily substance can dip into the bilge. Now if you were not out very long and there was water in the bilge, cut for leaks and also check for a soft transom. Might need to rebuild it while the motor is out