Reply To: What issues can cause surging?

[Don]

Well, first I would like to know when the last time the engine ran normally, or has it behaved like this ever since you have owned it… Next, I’m wondering how it idles….It would seem like any sort of crankcase leak/seal issue would show up more at idle/low speeds than at higher speeds. After re-reading your post, you mention the engine starts and idles just fine. You also mention changing both crankcase seals, how did it idle before the seals were changed?
Next, I am wondering if this is one of the Gales with the combination of remote and integral fuel tank. If so, I would be suspect of the fuel lines/plumbing on the engine. Pumping the fuel bulb won’t necessarily overcome some sort of obstruction in the fuel lines/connector or carb…You must have a heck of a grip, I surely have never been able to overcome the carb/float with the primer bulb… Do you have the float level set correctly? I have heard of floats being installed upside down, but don’t know if that is actually possible. What type of filter does the fuel system have? Does it have one of those “sintered filters” in the glass bowl under the carb? If so, remove it and retest. Have you tried a different fuel tank/line? What about the choke linkage? Some of these engines have funky linkages, perhaps the choke valve is fluttering slightly at WOT.
Your symptoms surely seem like some sort of fuel restriction issue, but anything is possible. A sloppy mag plate could cause WOT timing to vary just a bit. Does this engine have a stop switch? If so, unplug the leads and retest. I am assuming that you have checked compression and it is OK. A water leak into the crankcase/cylinder(s) could cause an issue like this, but this is a very remote possibility. Try running the engine at WOT and let it misbehave for awhile, then shut it right down and pull the plugs to see if they both look the same…
Feel free to post some pictures as well…D