115 v4 Sputtering at idle/low rpm

[Hardcore]

motor is a 1991 VRO2 115 Johnson. first it idles around 550rpm and runs rough and "spits" at that speed and often dies. it is hard to restart unless I open the throttle up a little. it gets up and goes pretty good and runs fine on a plane. when i popped the top i see that the carbs are wet with dripping gas.

the motor has new plugs, water filter, fuel filter. Any ideas? I'd like to just buy 2 new carbs and be done with it. Thanks crew

 

[crb478]

Re: 115 v4 Sputtering at idle/low rpm

I think that you will be fine rebuilding those carbs instead of buying new ones. Pay particular attention to the low speed jets it sounds like they are colgged to me. Do a good thorough rebuild making sure to get all the passages spotless and it should run great.

 

[wavrider]

Re: 115 v4 Sputtering at idle/low rpm

Carbs, Carbs, Carbs.
My 1978 115 was doing the same symptoms as yours. Good carb rebuild, lots of soaking, carb cleaner and compressed air through the jets, re-assembly with gaskets and now the ole 115 purrs like a kitten.
Just rebuild them and you should be good to go.
This will solve the sputtering at idle but somehow they got dirty so also recommend you look at your gas lines, fuel pump, and tank. If you have a filter or water separator check these items also for deterioration.

 

[HighTrim]

Re: 115 v4 Sputtering at idle/low rpm

I agree with the carb rebuild. Pay attention to those jets as stated, as well as the float level setting as per your manual. That is what sounds probable to me. When finished give her a good decarb. You can find the instructions for that in the FAQ. Good luck.

 

[iwombat]

Re: 115 v4 Sputtering at idle/low rpm

This sounds like nothing more than a float adjustment to me. Still, while your in there give them a thorough rebuild and cleaning.

 

[Hardcore]

Re: 115 v4 Sputtering at idle/low rpm

hey wombat, i see you are from North Bend, I hail from Covington. Nice to see some locals among this predominately eastern forum.

Does anyone have a recommendation on jet size or should i stay stock? i used to hear people say you can make a ____hp into a ____hp just with jet changes.

thanks for the help all.

 

[ondarvr]

Re: 115 v4 Sputtering at idle/low rpm

There's no truth that rumor of changing jets for more power, it's out there and you will here it frequently, but jetting is either right or wrong. Occasionally minor adjustments can be made to improve how a motor will run, but it's not a big HP increase, just running better for your location, altitude mostly, so keep it stock.

 

[iwombat]

Re: 115 v4 Sputtering at idle/low rpm

How is it over on the other side of the hump?

Keep your stock jet sizes unless you're going with some aftermarket reeds.