Just need a sanity check

[Enginefixer]

Have a 1979 100HP Johnson that ran great last year after a little TLC. Took it out the other day and ran great for about an hour, then wouldn't idle and died. Luckily someone took pity on me and towed me back to the ramp. It would barely run with the fast idle lever and would die at idle. Once back at the house, checked compression, 125 all 4 holes, plenty of spark (7/16"). Noticed that the previous owner had skinned the fuel hose from the inlet fitting to the fuel pump so the hose clamp would fit, so replaced that and noticed it was cracked by the hose clamp. Hmmm. Anyway, made up a rig to check fuel pressure and vacuum. Ran on the muffs with the gage hooked up first to the suction side of the pump and then on the pressure side of the pump. Suction was 0" at 2500 RPM, pinched the hose and got it up to around 7". Discharge side of the pump was 3-3.5 PSI at 2500RPM, and could get around 5 when pinching off the hose. No bubble is the fuel so I know that the system is tight. Had read that 5-7 should be what it I should see for pressure, but I am sure that is with the engine in the water. Since replacing the hose that supplies the pump it seems to run way better on the muffs, and hope to get it in the water later today and see what the results are.

Have I missed anything that anyone can think of. Carb rebuild is the next logical step. Thoughts? Thanks!

 

[Vic.S]

I'd be hopeful that the troubled were caused by air being sucket in through the crack in the fuel hose and that all will be well now that is replaced. You'd have probably kept going by pumping the fuel line bulb.

 

[Enginefixer]

Pumping the bulb​ did not seem to make any difference, trust me I tried. getting ready to bring it back to the water and see how it does on the trailer. If it stays running with the engine submerged, I may get brave and untrailer it. No guts no glory. :laugh: