1997 50HP Johnson loses and regains rpms @ wot

[andrewi]

When running @ wot, engine stalls to low rpms and suddenly opens to wot after running at under 2000 rpms. Engine sits most of year without running. It is hardly broken-in. Any suggestions? Thanks

 

[plywoody]

Re: 1997 50HP Johnson loses and regains rpms @ wot

Check condition of the spark plugs, but my guess is you have gum in the carb from gas sitting in it, and it is going to take a carb rebuild and a good cleaning.

 

[rickdb1boat]

Re: 1997 50HP Johnson loses and regains rpms @ wot

Could be bad primer bulb, Clogged fuel tank vent, fuel pump, bad gas after sitting so long, carbs need rebuilding. First thing I would do is replace the fuel line assembly and check the vent. Also, run a portable 6 Gal. tank with fresh Fuel/Oil mix(50:1). If that does'nt do it, when you're running and it starts to die, have someone with you pump the primer bulb and see what happens. If it goes, may be the fuel pump. Also, when it dies, check the condition of the primer bulb. Is it still firm or is it collapsing? A little more info on what you have tried will help us diagnosis your problem. Let us know!

 

[andrewi]

Re: 1997 50HP Johnson loses and regains rpms @ wot

Plywoody and Rickdb1boat, thanks for the replys. I let the boat sit up once before and it cost me $183.24 to have the carbureators removed/cleaned, new plugs, unstopped aerator nozzle, changed gear lube, and water tested. I had heard that something could be wrong with the electrical system and have already put it in the shop, but wanted different opinions. I think its going to be in the fuel system. In addition, I have ordered a service manual for the future. Again, Thanks, Irao

 

[clanton]

Re: 1997 50HP Johnson loses and regains rpms @ wot

Check the VRO pump pulse hose behind the starter, sometimes the starter housing rubs a hole in the hose. Check the power pack wires from pack to coil for bare spots. Disconnect tan wire to powerpack to bypass S.L.O.W.

 

[plywoody]

Re: 1997 50HP Johnson loses and regains rpms @ wot

After you get it fixed, I'd do a search on this site for "winterization" before you let it sit for any length of time next time.<br />Letting any engine sit for extended periods of time without proper preparation and maintenance is not good for them. And gets expensive.