1987 28hp Johnson - hesitation, restart troubles

[pplkook]

All

I have a "new to me" 28hp johnson where we have done a full tune, rand some sea foam through it, re-synched the carb/ignition, new plugs, new impeller and a new thermostat. For the most part it runs great, especially at 3500-WOT. The is only one issue left to sort out.

Intermittently at low RPMs in gear (1500-2000 RPM) there is a short reduction in power - sputter, and then runs fine. It isn't consistent by any means. And at times after hard running with a quick shutoff, if you wait to restart, it can have trouble re-starting and requires starting in neutral with more throttle. After each scenario when running it is more "smokey".

I was thinking that maybe it is a fuel pump issue where there is a leak from the fuel pump into the crankcase which makes the mix too rich for an instant?

The manual says that the fuel pump can not be serviced, but looking online they do make a "repair kit" for half the cost. Would you buy the pump or the kit?

Any advice is greatly appreciated.

-Jack

 

[WillyBWright]

Re: 1987 28hp Johnson - hesitation, restart troubles

When I do it for myself, I do kits. When I do it for customers, I do whole pumps. With labor charges involved, a whole pump is more cost-effective. Kits are more cost-effective when a labor charge isn't a factor.

I'm not sure that's going to solve your problem, but I'll never argue against rebuilding a 20 year old fuel pump. I think you have a sticky primer that isn't closing all the way. With the motor running, remove the primer hose from the motor (the fitting on the primer breaks easily). If it continues to dribble, you might need a new primer. They can be rebuilt too.

 

[tashasdaddy]

Re: 1987 28hp Johnson - hesitation, restart troubles

you ran seafoam thru it, but did you do a complete decarb with the seafoam deep creep. 20 years old it needs to be done. get the built up curd out, the smoke may be the build up getting hot after the stop.

 

[pplkook]

Re: 1987 28hp Johnson - hesitation, restart troubles

you ran seafoam thru it, but did you do a complete decarb with the seafoam deep creep. 20 years old it needs to be done. get the built up curd out, the smoke may be the build up getting hot after the stop.

Sorry I forgot to mention that as well. We ran seafoam in the gas - AND did the deep creep spray treatment recommended on this forum. Basically followed the recommendations that most of you guys post when getting a "new old" engine.

 

[rickdb1boat]

Re: 1987 28hp Johnson - hesitation, restart troubles

Since it's new to you, I would pull the carb off and give it a cleaning and rebuild. They are so easy to do, it's well worth the time. You can also inspect the lines then...When it does this sputtering, pull the plugs and see what they look like and report back..I have a 89' 28 special and it's been a great motor....

 

[tashasdaddy]

Re: 1987 28hp Johnson - hesitation, restart troubles

i think if the fuel pump was leaking it would flood out at high rpms also. right now i voting leaking primer.