1988 johnson 88spl won't idle

[walkinstick]

I have a 1988 johnson 88spl that will not idle. I have checked compression [125+ all 4] spark jumps 3/4 inch gap, rebuilt and eventually replaced carbs, checked and replaced hoses as needed, rebuilt fuel pump. finally gave up and took it to the shop and was told my lower crank was bad nd was causing my problem. I brought the boat home removed power head and found base gasket had blown out and leaking into water jacket, main seal seems ok but will replace anyway,why not. My ? is this, could the gasket or the lower crank seal be causing this motor to not run at idle. thanks

 

[walkinstick]

Re: 1988 johnson 88spl won't idle

asd

 

[emdsapmgr]

Re: 1988 johnson 88spl won't idle

A bad base gasket can fill the cowling area with black exhaust smoke-which will get reintroduced into the carbs thru the airbox-which certainly can affect idling and running. Not really a good idea. See how it idles after you replace the base gasket. When idling, the carb butterflys are closed. Fuel passes thru small dedicated passages in the upper carb bodies. These small passages are susceptible to accumulating dirt and old/dried fuel. Once a passage become restricted, the engine won't idle well. An aerosol carb cleaner blown thru these passages will usually do the trick.