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ChadS
03-19-2005 09:04:12
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Re: H, Engine RPM under load low in reply to 230,H,M, 03-19-2005 05:01:34
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Your governor high load rpm is not adjusted correctly. it is still too slow. Take off the governor plate, and back out the bottom bolt about 3 full turns, then tighten the jam nut. also, check you throttle linkage to where it bolts to the head, the rod, may be hitting the manifold. To really get the most out of it on the dyno, and really help the engines running charateristics is to properly set you carb, timing, and governor to what this engine requires to run best. Each engine, is its own, Not all engines run exactly the same, one size, dont fit all in this case. Different adjustments do different things to help increase performance. Ive dyno tuned alot of C's H's, M's, Supers, stock, to modified. What I have found, is that the carbs are not jetted right to properly run an engine at full load, they are always lean, not enough fuel. The Stock governor springs you get from IH are just as bad as an old worn out one. To properly dyno the engine, the rpms, should go just a bit over what rated rpm is, in this case, the H is 1815 at 540. Most H's wont ever get that high in the first place, mite see what you described, low rpms where they should be higher. With no load, the pto rpms speed should go up to about 595-615 rpm, then pull it down to 540 rpm. I bet your carb will be very lean at this point, because the governor will now do its job and hold the carb open more, it takes more fuel, to run a higher rpm under a load, the stock jets in the carb, they will work for under 1500 rpms, you can se the rpm back down when your finished if you dont like it to run that fast, it would be under 2000 if left at that speed, you could set the dyno, (no load) and then set your hand throttle to where 540 is on the hand lever. Mark the notch, or if you have an M&W style throttle, remember the number it was set to. I think you will have to rejet the carb, double check your valve lash, If it a 152, 32-35 hp, if you leave it like it is, 35-39 if you step up the governor. and tune the carb to that faster rpm. What happens is, the carb is open more under a load because the governor is now being pulled down to rated rpm speed, and responds more to a rpm drop. Hope this helps, CHadS
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