1991 Marathon wont rev up

[2horse]

I have a problem with 3pg engine. Compression is good tried 2 different carbs and I have spark. It will start up but runs horrible and will not rev up. Same results with no belt and no muffler. It has the HEI conversion but has worked fine before. Is it possible something can throw the timing way off? I have tried with starting fluid to try and get some rpms and no luck. Spark seems to be good with plug pulled nice and bright. Thanks in advance

[cart around]

You say it's running, but is it? Is the exhaust getting warm?

Won't do anything on starter fluid. Either the crankshaft seals are bad, or you put the piston in backwards.

[2horse]

Yes it is actually running and getting warm . Crank seals new and piston in correctly. Thanks

[Dabble Inn]

Is the fuel pump pumping fuel adequately?

[2horse]

Fuel pump working good. I tried a spare just to make sure. Pulled line off carb and checked. It is like timing is way off or something but not sure what can throw it off. Can hei module effect timing?

[cart around]

If the timing is way off, it would run great in reverse. You can try that, and try reversing the red and blue pulsar wires to see which way runs best.

[2horse]

Runs pretty much same in both directions. I tried switching wires also. I have been messing with this thing a lot and have researched lots. What is reason it would run better in reverse if timing was a problem. Also is there a way to check crank seals other than visual? I had replaced them last summer when I had engine out to work on clutch so I assume they would be fine.

[2horse]

I see how to test seals was just typing and not thinking sorry for that. will try again this weekend. Thanks for the input