97' OIS 150 hp leaking fuel after shut.down

[Bob Gilvary]

Fuel/oil mix seems to be coming from the carb venturies at all 6 after shut down. I've looked and cleaned everything I can think of, but over night, I've got the fuel mixture running down the leg, and puddled inside the cowling.

Can anyone point me in the right direction to eliminate this problem?

 

[SparkieBoat]

Re: 97' OIS 150 hp leaking fuel after shut.down

remove your carb cover, pump your bulb hard, look for a leak. if the engine is running fine, that could just be fuel in your carb bowl leaking out when you trim it up.

 

[Haffiman]

Re: 97' OIS 150 hp leaking fuel after shut.down

Check you vapor chamber, float settings and ventilation. If pressure in the float chamber, carbs will 'leak' after shut down when tilted.

 

[Bob Gilvary]

Re: 97' OIS 150 hp leaking fuel after shut.down

remove your carb cover, pump your bulb hard, look for a leak. if the engine is running fine, that could just be fuel in your carb bowl leaking out when you trim it up.

I've done that, and find no leaking. The bulb gets hard.

I just came back from checking on that engine. The motor was left over night in the full down position. A small puddle had accumulated to the rear of the lower cowling, and a little puddle right under the carb cover where it couldn;t run to the rear of the cowling. The rubber connecting rings from the carbs to the cover were showed signs of fuel, and some of the lower carb bodies showed signs of fuel.

From all indications, it's coming from the front of the carbs. I just don't know why it's such an excessive amount, after shut down.

 

[Bob Gilvary]

Re: 97' OIS 150 hp leaking fuel after shut.down

One more thing I forgot to mention, and it could be important to the issue. There's excessive carbon at the exhaust. Carbon build up inside the prop and anywhere the exhaust comes in contact with or near the white paint of the lower unit. This is not unburned fuel, like a dead cylinder would show, but thick carbon.

Other than the rich condition and fuel collecting in the cowl, I see no reason to not run the boat. I'll get a report after the run and see if anything's changed.

Haffiman, thanks for the input about the vapor chamber. I also thought, due to the rich condition, that fuel might be bypassing through the primer solenoid.