Performance problems on a 83 Big Red 200E

[polaris_dave]

I once did the rings on a 200. It's not too hard of a job. I think I was 17 at the time, LOL! Just make sure they are installed on the piston properly.
Drilling out a jet is a bad idea. They are sized based on flow, not hole size. The chances of getting it right are slim.

Thinking about this some more, if your compression is low, then usually an engine will be hard starting and won't idle properly. An engine with low static compression can still run fine at higher rpms. If it runs better on half choke, then that sounds lean. I would try dropping the clip on the needle again now to see what happens. That will richen you up from throttle opening to at least 3/4 throttle.

[polaris_dave]

When you are testing compression, make sure you hold the throttle wide open and keep turning the engine over until the needle stops moving, but I'm assuming you already know that.

[Grizzlypeg]

Check for vacuum leaks by spraying carb cleaner or wd40 around the connections between the carb and the cylinder while its running. If it suddenly affects the idle, you've found your air leak. The backfiring and choke needing to be on suggests a lean condition. That could either be fuel not getting through the carb because a jet or passage is plugged, or air is leaking into the intake somewhere.

[frenchy]

I'll retest with that procedure, didn't know that. We did check for a vacuum leak with carb cleaner and didn't find any trace of a leak.

[Grizzlypeg]

If there are no intake leaks, and the jets aren't plugged, Test or retest fuel flow from the tank. It should flow fast with a full stream of gas. After that, I'd also be wondering if the needle and seat or float are hanging up and fuel level is low in float bowl. Sometimes you can stick a clear plastic hose in the bowl drain and hold the open end up high above the carb. The hose will show the level of fuel to which the bowl fills. Start it up, and watch the fuel level. It should be up around the gasket / parting line of the fuel bowl (approx). If its way lower, then there is a problem with the float / needle / seat hanging up on something.

[frenchy]

Originally Posted by Grizzlypeg

If there are no intake leaks, and the jets aren't plugged, Test or retest fuel flow from the tank. It should flow fast with a full stream of gas. After that, I'd also be wondering if the needle and seat or float are hanging up and fuel level is low in float bowl. Sometimes you can stick a clear plastic hose in the bowl drain and hold the open end up high above the carb. The hose will show the level of fuel to which the bowl fills. Start it up, and watch the fuel level. It should be up around the gasket / parting line of the fuel bowl (approx). If its way lower, then there is a problem with the float / needle / seat hanging up on something.

I tested the fuel flow from the tank a few times and it runs nicely. I'm going to re-test the compression tonight with the throttle open and i'll report back.

Thanks much everyone for the help!

[frenchy]

Compression was at 130psi at best with the throttle wide open. Still short of the 156psi spec in the manual.

[Grizzlypeg]

Originally Posted by frenchy

Compression was at 130psi at best with the throttle wide open. Still short of the 156psi spec in the manual.

I don't think that is your problem. 4 stroke engines will run quite well when they are slightly off on compression. 130 psi should be plenty.

[frenchy]

Originally Posted by Grizzlypeg

I don't think that is your problem. 4 stroke engines will run quite well when they are slightly off on compression. 130 psi should be plenty.

Hmm well then. Carb removal, disassembly and re-clean #11 LOL

Not sure what to do anymore

[polaris_dave]

Is the engine timing procedure just for a set RPM? Do you have the timing curve for the engine? I would verify the curve at different RPMs. There might be something fishy with the mechanicals of your timing advance. The springs and some of the parts under that cover were all rusted out on our old 200. I replaced the entire advance unit with a better one I found on e-bay, actually off a 200x, which was the same.

[frenchy]

Originally Posted by polaris_dave

Is the engine timing procedure just for a set RPM? Do you have the timing curve for the engine? I would verify the curve at different RPMs. There might be something fishy with the mechanicals of your timing advance. The springs and some of the parts under that cover were all rusted out on our old 200. I replaced the entire advance unit with a better one I found on e-bay, actually off a 200x, which was the same.

Hmm. Now that you mention it, the pulse generator was super rusty. Maybe i'll throw in the one from the other engine! Stay tuned for that result! Good call by the way!

[Grizzlypeg]

We're all pulling for you!

How does a clean plug look after you run the engine for a bit?

[frenchy]

Without the pulse generator change, it's black and sooty.

[Grizzlypeg]

Originally Posted by frenchy

Without the pulse generator change, it's black and sooty.

Weak ignition results in unburned fuel and the appearance of richness. I was wondering if it was looking overly lean (because of the observation of needing the choke to be on.)

[frenchy]

WOOOOOOOOOOOOOOOOOOOOOOOO!!!!!

It was totally the CDI pulse generator! I took the one from my spare 200S engine and cleaned it a little with WD40, wire brush and then brake cleaner and BAM, started like a champ, idled like a kitten and had throttle response like a fox!

Thanks to all for everyone's input in making this work for me! I'll post a vid tomorrow when I can get back on it!

[Grizzlypeg]

Right on. Get out there and enjoy it.

[3Wheeler]

That's great news! enjoy!