1991 Johnson 150 GT

[ga284]

Went fishing today. About half way through the day boat started acting up. Was going to move to a new spot. After cranking, while idling past some boats close to me, boat started acting like it was flooding or missing. It finally cleared up, but after getting on plane, it was like the boat lost all spark or fuel and sat down. It would finally clear up and run. It did this several times before I put it on the trailer. Anyone else ever experienced this ? Any help would be appreciated.


Thanks

 

[BASS MAN]

Carbs need cleening out

 

[275prostratos]

carb float sticking

 

[south599]

So it idles really rough? When it did it on plane was it at a certain rpm. I had a powerpack slowly die it get overheated at a certain rpm then id lose the right bank of cylinders i could just barely keep the motor idling. I could stop the motor wait for a few and then start it up again and go. It eventually got worse and worse till i was able to diagnose it on the trailer

 

[ga284]

When it first started doing it the motor was idling fine. When it started acting up it would act like it was missing or flooding. I could not even keep it running. Finally got it running and put in gear. It was running really rough but eventually cleared up and ran smooth on plane at WOT for a short distance then just lost all spark or fuel and came off plane just like I set the boat down. Had to crank and idle several times before it cleared up again. Finally ran good enough to get on plane and get to the boat ramp. At the ramp could not keep it running long enough to power load. Had to winch on the trailer.

 

[south599]

Need a spark tester to determine if its the electircal system or fuel.

 

[ga284]

Yeah , I'm going to get one this week.

 

[nate2800]

Think it's getting hot? Had a 92 and the impeller needed changed. I would get it on plane and run and after a few min it would start missing when it would get hot

 

[ga284]

It had a new impeller put in last summer. The more I think about it, I think it may be fuel related. When it first started acting up at idle speed it started smoking really bad like it was flooding.

 

[jbh3]

Might also check into changing your fuel line and primer bulb to the newer ethanol resistant components. Get your parts from someplace other than Walmart - preferably a boat shop.

 

[ga284]

Changed the lines and bulb about a month ago. Got them from boat dealership.

 

[south599]

Be careful its not the gray ethanol line! Also a primer bulb that is carb specific as well. I run a fuel/ water seperator as well as pure gas, a cleaner stabilizer, and a synthetic oil.

 

[ga284]

I just have a regular fuel filter inline. I may check into fuel/water separator. I have been running pure gas with stabil additive. I picked up a spark tester at lunch. Going to check spark this evening. If spark checks out ok, I guess I will clean and rebuild carbs. Trying to decide if I want to tackle that myself or take to the shop.

 

[ga284]

Checked the spark tonight. First cylinder I checked jumped a good blue arc. The next cylinder on the same side was not arcing consistent. It would arc on the plug but not with the tester set at 7/16. The other bank had a very weak inconsistent spark. I had to close the gap on the tester to get it to spark. I hit the power pack lightly with a screwdriver and the spark got better but still not a good blue spark.Tested all 6 cylinders the right bank had a stronger spark but it not consistent . Is there any other way to test power pack?

 

[south599]

Switch sides. If the symptoms follow the pack then there you go

 

[ga284]

This particular motor only has one powerpack.

 

[south599]

Besides getting a spare to swap and test you would need an OHM meter and a shop book to read the OHMs before and after the pack.