no WOT on RDE-19

[tgissel]

I have a 1957 Johnson 35h.p. that will not rev up past 2650 rpms. I have rebuilt carb, checked armature plate under flywheel, and throttle linkage itself. Could the float be incorrectly adjusted? Any suggestions?<br /><br />Thanks, Thad

 

[Paul Moir]

Re: no WOT on RDE-19

Your rpms are so low I would suspect ignition. Try grounding out one of the plug wires and run the engine up under load. Then switch and try the other cylinder. Then you'll know that one cylinder is not producing power. If it's not compression, then it's spark may be failing under load.<br />It's not uncommon for this to be caused by cracked ignition coils. Remove them and carfully examine them. New ones are available from NAPA autoparts, Johnny/Rude dealers, and Iboats (cheap!).<br />Some people have reported similiar symptoms when they used automotive spark plug wire rather than metal core stuff. Did you replace the wires when you had the flywheel off?<br /><br /><br />I doubt having the float incorrectly adjusted would cause such a problem, unless you were running excessively rich from gas leaking past the needle and seat. But you would be seeing gas leak out the front of the carb when you primed it if that were the case.

 

[tgissel]

Re: no WOT on RDE-19

I have not changed the plug wires, but when I had the flywheel off, the coils looked new, the reason for taking the flywheel off was the bottom cylinder had no spark, but I cleaned the inside of the flywheel and it started working. The reason I keep asking all of the carb questions is this carb was in pieces, the needles are questionable one is pointy like I think it should be while the other looks like the eraser end of a pencil?? If this is correct which one should go where? Thanks

 

[Paul Moir]

Re: no WOT on RDE-19

No, that's what the 'needles' should look like - the idle oriface one is pointy and the high-speed one is very blunt.<br />I don't think you could possibly swap them since the idle one is much longer than the high speed one. <br />But if there were some way that the engine was running very rich, then that would give you that sort of poor performance. There's only a few possibilities for that - sunk float, leaking needle and/or seat. Of course leaning out the controls would improve the situation in that case. <br />When you've got the carb back together, try running the engine on one cylinder. That should tell you for sure whether you have a carb problem (common to both cyls) or an igniton/compression/exhaust/primary compression problem.

 

[rwise]

Re: no WOT on RDE-19

Have you tuned the carb? you may need to change the position the knob sets in. There is a post that gives great details on tuning these.

 

[tgissel]

Re: no WOT on RDE-19

O.K. this means I have the carb needles placed in the right location, Paul I will try grounding out one cylinder to see if I can figure out the problem. RWISE I have tried changing the knobs. Thanks