Lost RPM'S

[atlbraves70380]

I have a 1989 Johnson 150 GT. The VRO has been disabled and I run pre-mix. I have lost about 800 RPM'S going from about 5800 WOT to 5000 WOT. I have 110 compression on all six cylinders and fire to all six cylinders. Motor still runs, but it is very sluggish on hole shot now and not getting the top end I used to. Nothing has been changed on the motor from the time I had 5800 to the time I lost it.

 

[farginicehole]

Re: Lost RPM'S

I'm sure you'll get plenty of help here, but did you just get the boat out of storage for the season? If so, maybe your carbs are gummed up?

 

[atlbraves70380]

Re: Lost RPM'S

No, i live in the South and the boat runs year round. It was running fine and then poof rpm's gone.

 

[Dhadley]

Re: Lost RPM'S

Welcome!!<br /><br />Isnt Morgan City where Evolution Marine is?<br /><br />Anyway, you say theres spark to all cylinders. Is that at cranking speed or while the motors running? At what rpm?<br /><br />When was the last time it ran OK?

 

[atlbraves70380]

Re: Lost RPM'S

Yes, it is home to Evolution Marine. The spark is running it on the muffs in the driveway. It seems as though it has been losing power for about a month. I changed plugs and even emptied out gear. No water in hull. I did replace head gaskets about three or four months ago, but it ran fine after that. Someone told me that a weak battery could have some effect on it???

 

[markvan]

Re: Lost RPM'S

I had a 225 evinrude that did the same thing, ended up being some bad gas, emptied out the watered down gas filled her up with some new gas and in a matter of 5 min of running all was fine.<br /><br />A friend of mine also has a similar case but he lost about 2000 rmp, he replaced his fuel pump and the problem went away.

 

[atlbraves70380]

Re: Lost RPM'S

thanks for the info. I have run a few tanks through it, but I will look into the fuel pump. I see that you are a PO3 walleye, what rate? I did four years on a gator as a QM.

 

[markvan]

Re: Lost RPM'S

atlbraves the po3 designation comes from the number of posts you put on here, the more times you post the higher your ranking goes........