1990 40 johnson starts & idles good, but dogs speed or worse at WOT..what's goin on?

[atsmaboat]

1990 40 johnson starts & idles good, but dogs speed or worse at WOT..what's goin on?

This motor is running nice with muffs...also runs great at start, idle, etc out on the lake but when throttle up just can't give me any speed or force...I would guess it does about 1/2 of full throttle. Help please...frustration plus...BTW comp. test showed 120 on both cyl....could it be a bad gas line from tank??...just wondering cuz the one on my boat is just a bit brittle, checked, worn, etc. Ideas, suggestions, etc all welcome. Please don't tell me it's the VRO pump like a dealer jumped to right away..."oh we replace about one a day of those"...you gotta be kiddin me... I bet they like their 2 -300 bucks for it too, whether you need it or not.
C'mon man, it's just a fishing boat!!!

 

[Solittle]

Re: 1990 40 johnson starts & idles good, but dogs speed or worse at WOT..what's goin

Re: 1990 40 johnson starts & idles good, but dogs speed or worse at WOT..what's goin

Describe the troubleshooting that you have done. What you are askin for is guesses.

 

[atsmaboat]

Re: 1990 40 johnson starts & idles good, but dogs speed or worse at WOT..what's goin

Re: 1990 40 johnson starts & idles good, but dogs speed or worse at WOT..what's goin

Hey, sorry I guess I was askin for guesses...today, did a sea foam carb cleaner, new plugs, fingers crossed, went back out to the lake...and no improvement. However, I did put it in neutral & revved the engine and I did notice a bah, bah, bah-bah-bah. (And there were no sheep around nor was Pee Wee Herman.) So now I'm guessing or perhaps someone more knowledgable than I can ascertain that one of my cyls is missing. Since this game is fairly new to me...is that a correct assumption? So anyway where do I go from here for common cause of cylinder misfire. Help me if you can, I'm feeling down ...and I do appreciate you being round.

 

[atsmaboat]

Re: 1990 40 johnson starts & idles good, but dogs speed or worse at WOT..what's goin

Re: 1990 40 johnson starts & idles good, but dogs speed or worse at WOT..what's goin

Another ? I've just realized...what do each of these do & how do you test them...1. the stator. 2. the powerpack.

 

[atsmaboat]

Re: 1990 40 johnson starts & idles good, but dogs speed or worse at WOT..what's goin

Re: 1990 40 johnson starts & idles good, but dogs speed or worse at WOT..what's goin

Just thought I would finish this up with letting anyone who might need some info that might also have this problem, the lower cylinder was not firing at all. That was the bah-bah-bah I was getting at the lake when revved in neutral. I really was not experienced enough I guess to recognize the off sound when I just had it on the muffs here at home... course I couldn't rev it on the muffs either. So anyway, when I got back from the lake I tested on muffs with spark to each cyl. separately ( just took plug wire off 1 at a time) and top cyl was fine but bottom would not fire unless I added fuel mix thru spark plug hole and it would only fire as long as that fuel was present. So, at that point I realized it was a fuel problem & not a spark prob. Proceeded to pull the carburetor ( and even tho the OMC manual tells you to replace every screw with new, etc...I did not do some of that) But what I did find was the bottom of the bowl on the carb that contains the high speed orifice was very gunked up, with something almost like ear wax, is the best I could describe it. You can refer to the Top Secret File in the forum if you need more info...they do a pretty nice job of explaining. I didn't buy a carb kit or anything like that just cleaned out that gunk with some wire, sprayed it, and blew it out a bit. Oh, I may be wrong but I also did not create a special screw driver on the h.s. orifice like they say to do...I just used one that was small enough to fit into the orifice...seemed to work o.k. Also be careful putting the float & bowl back together, they do need to be turned upside down...see Top Secret file again. BTW the motor now runs almost as good as new!!! Hope this helps someone else who may have like issues.