1985 Supra Comp Issues - Black Smoke Low Idle

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06-03-2020, 08:26 AM
B5allen187

1985 Supra Comp Issues - Black Smoke Low Idle

For starters boat is an 85 Comp TS6M with a PCM Chevy 350.

So yesterday was dump in day - I was stoked. We backed her in and she fired right up. Felt like she was running like a top buttery smooth. No surging just straight velvet awesomeness.

Took 2 joyride laps around the lake (small lake 130 acres) and backed off the throttle to pick up my bro at the dock. Went to accelerate and the boat felt like it had nothing and sounded like it wasn't running on all cylinders. Started belching black smoke out of exhaust as well. I limped it back to the dock for inspection.

The only way I can start it is fully choked throttle all the way on and it runs rough when I do so. After inspection it looks like the carb has excess gas leaking around the seal. But there was smoke coming out of the carb as well when idling that was blueish in color.

Did I blow a ring or is this a carb issue? HELP I wanna ski!!!
06-03-2020, 10:54 AM
Jetlink

First of all, are you sure it is a GM 350 instead of a Ford 351W engine in there? I am not aware of Supra running anything other than Ford small blocks in their boats until the mid 90's or so. I would start with the simple first and do a Carb rebuild.
06-03-2020, 02:11 PM
B5allen187

Quote:

Originally Posted by Jetlink

First of all, are you sure it is a GM 350 instead of a Ford 351W engine in there? I am not aware of Supra running anything other than Ford small blocks in their boats until the mid 90's or so. I would start with the simple first and do a Carb rebuild.

Yes I'm sure it's a GM 350. I know super rare. The original owner told me very few were made with this motor - a local dealer confirmed this as well. I think a carb rebuild kit will be on the way!
06-04-2020, 07:01 AM
michael hunter

When I bought my 89 Sunsport a 350 chevy was an option. I am a chevy kind of guy but I opted for the ford engine because the 351w is an excellent choice for a boat and I knew 99% of the ski boats used ford and the chevy would be harder to get parts. Your problem sounds like the carb needs a rebuild. What brand of carb do you have ? What ignition do you have. Pictures would help .