115 runs on 2 cylinders

[ssschoeni]

I just rebuilt the carbs on my 1975 evinrude 115 because the boat wouldn't start and then ran terrible after getting it running. After reinstalling the carbs and taking it to the lake, it has no power amd seems to run on only 2 cylinders. The bottom 2 plugs seem pretty dry where the top 2 are wet when removed.( I had installed new plugs before I went ) What would cause this? Rebuild again with an entire rebuild kit? (A local dealer told me I only needed new bowl gaskets?) Maybe something in the reeds?

 

[rickdb1boat]

Re: 115 runs on 2 cylinders

Got spark on all cylinders??

 

[ssschoeni]

Re: 115 runs on 2 cylinders

Yup. I just rebuilt the carbs and it seems to run better. The fuel bowl gasket was covering the fuel inlet to the bowl. Is it normal for the carb to need have the idle adjusted down a fair amount after rebuilding? The RPM at idle was really high ( 1750 rpm ) after the rebuild so i adjusted down with the screw. Anything else i should be looking for?

 

[Cricket Too]

Re: 115 runs on 2 cylinders

Are you letting it idle on muffs or in the water? An engine will idle a little higher on muffs because ther is no back pressure, so you should make your idle adjustments in the water when the motor has back presssure on it. 1750 is pretty high so it needed to be adjusted but you may have to raise it if you did it out of the water. Good Luck.

 

[ssschoeni]

Re: 115 runs on 2 cylinders

I took it to the river. I still doesn't run right. It sputters at anything under 3/4 throttle. Also I can not get the idle to come down to where it should be. I think it may be in the control as it keeps pulling the warm up lever up but even pushed all of the way down it is still too high and the adjuster won't touch anymore. Is it possible that there is something up with the coils? The carbs have been cleaned and rebult and it still isn't right.

 

[ssschoeni]

Re: 115 runs on 2 cylinders

Also, I took a look and 1 coil has a fair sized crack in it. I've tried to find the coil for it but everyone seems to skip over the 1975 115 horse. Is it the same as the 1974?

 

[flech01]

Re: 115 runs on 2 cylinders

How is the compression? You may be droping a cylinder or two when you get it under a load.

 

[Solittle]

Re: 115 runs on 2 cylinders

Will the spark jump a 1/2" gap on all cyclinders as rick suggested?<br /><br />If you have solid spark on all 4 go for the complete rebuild on the carbs. Bowl gaskets don't even come close to a thorough cleaning & rebuild.<br /><br />Check your manual for sync & linc + carb adjustments + idle speed procedures.

 

[ssschoeni]

Re: 115 runs on 2 cylinders

Compression is 120 on all except # 4 is 116. I found a bad throttle cable and replaced it. The mechanic tried to explain how to sync the carbs. It is a bit better but still jerky. The spark seems ok and I don't see or hear any arching on the coils. I think I need the manual to get the carbs synched properly. Which manual is best can i get it on Iboats?