Loss of power

[Bjorn.]

I have a Johnson 30 hp 2 cyl. engine (1999 mod.) It is just running on one cyl. there is nothing wrong with the ingnition or combustion or spark plugs etc. It must be someting with the fuel supply, but how to analyse the problem and get it working again, and what spare parts is needed?

[lk2ds0n]

I can't help but wonder if some particulate matter or something might have gotten past the filter??? Possibly plugged the fuel inlet at the carb??? If I suspected a fuel supply to one of the carbs, I might disconnect the fuel line to that carb, then turn the motor over to see if fuel was getting delivered. If it is, then the plug is at the carb itself. You could remove the fuel reservoir under the carb (if your model has one), then turn the motor over to see if fuel is making it this far. From here you might have a better look to where on the carb that might need cleaned too.

Good luck!

[Bjorn.]

As far as I can see there is just one carb in this engine. I wonder if there might be some problem with the intake manifold and the leaf plate. The leaf plate is as I understand divided in two sections one for each cylinder, if one is not tight sealed the fuel is not sucked into that cylinder. The "leaf plate assembly" (0437712) does it incl. the two gasket needed to the crankcase? What is your opinion about my understanding? Rgs, / Bjorn

[guitarzan413]

It is possible that one jet is clogged. I would pull carb and clean.

[boats.net]

Originally Posted by Bjorn.

I have a Johnson 30 hp 2 cyl. engine (1999 mod.) It is just running on one cyl. there is nothing wrong with the ingnition or combustion or spark plugs etc. It must be someting with the fuel supply, but how to analyse the problem and get it working again, and what spare parts is needed?

It sounds like a leaf plate problem. The gaskets are not included.