1958 7.5 Johnson still having issues

SPK

Seaman
Joined
Nov 21, 2010
Messages
55
Hi again,
I am still working on my motor and am having some success. Yesterday on the water it was running pretty goood at both low and high speeds.
I tweaked the high and low speed jets under load and had her running pretty good. I left the water in good spirits and didn't tinker around anymore thinking I had solved the issue. The packing nuts are tight so that there is no play in the needles when set.

Today I took the boat out and started to experience difficulties at high and low speeds after touching nothing since the night before. Again, all lines for fuel and air are new and oil return line is newly replaced. Sea Foam is being used in every tank of fuel. The tank holds excellent pressure and when the cap is removed there is a good hissing sound as the pressure is released.

Today however I noticed something new while fishing in a weedbed. The motor was turned off and I tilted it up and to one side to keep it from catching on the weeds. Shortly thereafter I smelled gas and noticed fuel dripping from the the air silencer assembly. I am guessing that this might have happened because of the tilt of the powerhead and the fact that the fuel lines were still pressurized. Tilting the motor back down into the water stopped the dripping.

So should I experience fuel dripping as I have described? If not, what might be causing it?

Is this dripping somehow related to the way the engine inconsistently runs?

Could my float be sticking[probably the old cork kind]?

I have been looking around on the internet for a carb kit with the float but they , the float that is are a bit difficult to find.
I am open to suggestions and am willing to put in a new kit if you think that might be the issue.
I honestly think the problem is a fuel related issue. I get great start up from the motor and when it is running good it doesn't miss, so spark seems to be good. Trolling is usually not too bad but sometimes when I move from a troll to WOT, it doesn't take off, remains sluggish.
Hoping to hear from you soon.
Thanks,
Sean.
 

cr9c1

Petty Officer 2nd Class
Joined
Aug 28, 2006
Messages
146
Re: 1958 7.5 Johnson still having issues

Just my opinion but if it has a cork float, see if you can get a replacement plastic one. I have heard this new fuel is capable of eating the coating off the floats and at that point, a cork float would become saturated in fuel and not do its job, causing too much fuel to enter the carb and flood the engine out some. I got a plastic float for a 1957 18hp so you should be able to find one as well. If you haven't removed the core plugs and really deep cleaned that carb, it would be a good idea to get a rebuild kit (You can get oem kits with floats from a BRP/OMC/J/E/dealer) and rebuild it from the ground up with all new stuff. Needle, seat, core plugs, packing washers, float, gaskets, etc.

These carbs are very easy to rebuild and they work so well when thoroughly cleaned and rebuilt.
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: 1958 7.5 Johnson still having issues

If it is only doing it when you tilt the engine up, you can let the pressure off of your tank and that should cure your problem.
 
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