Engine seems to bog/miss on takeoff.

[dasimpleman7]

Hello i have a 1978 evinrude 115 power tilt and trim on a 16 ft hydroglass bass boat. When i give it throttle from a dead stop the motor seems to cough and miss then after a 5 or 6 seconds seems to clear up and plane off. Once it planes it runs like a top! It does this cold or hot. I pulled the plugs and they seem oily. And one more thing when the engine is idling you can see smoke from the exhaust like theres too much oil in the gas, what is the correct fuel/oil mixture for this engine? And what could be causing the hesitation from a stop? Could it just be the plugs being a little oily?

 

[tashasdaddy]

Re: Engine seems to bog/miss on takeoff.

50:1 is the correct mixture. there are a lot of things, and combinations, that could cause your hesitiation. you need to check compression on all 4 cylinders, when was a link n sinc last done? have you check spark on all 4?

this is for future reference:

Ethanol and fuel lines
replace all fuel line with Alcohol resistant lines. Ethanol deteriorates, the rubber lines, then they start to sluff off on the inside, going directly to the carbs. Settling to the bottom of the bowl. Contaminating the carbs high speed jets. clean a rebuild carbs, flushing fuel line before connecting to carbs.

 

[dasimpleman7]

Re: Engine seems to bog/miss on takeoff.

thanks for the quick reply, i did check compression and all is fine there all with 5 lbs of each other. i have not checked spark on all cylinders, i just pulled the plugs and seen the oily resudue on them. i dont know the last time they were changed. Im going to install a fresh set of plugs and see if that does the trick. the motor was completely rebuilt and refurbished about a year prior to me purchasing it. I found the rectifier to be trashed im guessing the battery cables got crossed by the previous owner. Would the bad rectifer have anything to do with it? Im sorry about my ignorance but im new to working on outboard engines. I installed an inline filter on the fuel line right before it enters the engine to collect any contaminats from the line or tank. Will check for strong spark and post results, thanx again for the speedy reply.