1978 115 Johnson Throttle Problem

I have a Johnson 115 (1978) new to me. It was installed by the marina where I purchased 2008. It throttles fine in low and hi range but when it gets to a certain point, about 5/8s to 3/4 of the way forward, the engine stalls. Sometimes if I manually choke before it gets to that point, it will continue to operate. The fuel pump has been rebuilt, the gas line from the fuel pump to the tee fitting going to the carbs has been changed, the marina changed a power pack, the carbs have been cleaned, a separate in line fuel filter has been installed, and it still continues to stall. Sporatically the bulb will not become firm when squeezing to fill the line with fuel.

Re: 1978 115 Johnson Throttle Problem

I suspect you still have a problem with your carbs. Either a clogged jet, or a mis-adjusted or stuck float. The bulb issue points to a float problem.

Re: 1978 115 Johnson Throttle Problem

Thanks Is it something I can do myself? Never attemped removing or working on a carb.

Re: 1978 115 Johnson Throttle Problem

I think you're the only one that can assess that. What other similar kinds of things have you successfully worked on?

Re: 1978 115 Johnson Throttle Problem

I have replace all the gas lines from the connection at the motor and have removed and rebuilt the fuel pump (motor worked after rebuild)

Re: 1978 115 Johnson Throttle Problem

Carbs are really no harder than the fuel pump. If you were comfortable doing that, then you're probably ok doing the carbs. Do you have a service manual?

Re: 1978 115 Johnson Throttle Problem

I do have a service manual. I looked on the johnson/evinrude site for parts and for the 115 they asked if it was a 115890C, 115893C, or 115899C carb. How do I know which one? Also, there was a similar question in the forum and the answer given to the poster was it may be a throttle cable problem. It this also a possible problem here?

Re: 1978 115 Johnson Throttle Problem

A throttle cable will manifest itself at one extreme of the range or another. i.e. can't get down to idle, or won't open up all the way. You've got a dead spot in the middle of the range, and a bulb that sometimes won't go hard when pumping. The bulb issue is either misadjusted or bad float, or a torn diaphragm in the fuel pump. Pair that with the dead spot, and I'd be suspecting a carb flooding out.

As for the kit. I'm not really sure how that would matter. Maybe someone else knows better, but a carb kit for a '78 V-4 should cover all the crossflows.

Before you go tearing into the carbs though. This could also be leaky fuel lines. Double-check all your connections while pumping the bulb and make sure you're not leaking anywhere.