After a 20 year hiatus from the hobby, I recently took an old K&B .61 out of a long long storage. I bought the engine new, ran it long enough to break it in, put it away, and only recently dug it out again.

The engine turns over freely and has good compression. However the front bearing is really really sloppy. Fuel will leak out of it.

I hooked up a new freshly charged Hot Shot 2 and a tank of new Omega 10% fuel. I tested the Hot Shot and it works fine.

The glow plug is a new Fox idle bar plug, screwed in good and tight.

I set up the high and low speed needle valves as close as I could to factory settings, and blew through the fuel inlet to make sure that it is not too clogged.

I tightened up the carb nut to keep air leaks down.

Only after a massive amount of priming, maybe 10 or 20 revolutions, will the engine kick over, complete one or two revolutions, and die. I maybe got it to run three seconds on one occasion.

The results are the same whether the tank pressure line is hooked up or not.

I played with the high and low speed needle valves but not much seemed to change.

The engine is definitely getting fuel; I can feel fuel leaking from the front bearing.

Where am I going wrong here? If the engine wants to start, I must be fairly close. I have a sneaking suspicion that I am almost there, something not quite adjusted right....

Prawn:

Need a little more info before commenting. What carb does it have? It could be black plastic, a flat sided aluminum block with "K/B" on the front, or it could be a ribbed casting with "K&B" in a oval cast into the front.

If yours is the black plastic, it could be either of two. From the front of the engine, looking down at the top of the carb, does it have one screw sticking up near the throttle lever and a second near the fuel nipple?

If it has the TWO screws it wont work without a pump, and the engine should have a Perry VP-30 pump built into the back plate.

If it has only the one screw near the throttle lever it will work fine with muffler pressure.

The "Ribbed: carbs have two variants, front or rear mounted needle valves, in use they can be considered the same.

The pictures should help the ID of the carb.

Bill.

Take the idle bar plug out, and throw it as far as you can into a wooded
area with your eyes closed....or give it to someone you don't like.

Put in a K&B1L plug, a Tower long r/c plug, or a Fox Miracle plug. If you
want the engine to run really well, do the same thing with the carb, and
replace it with a Magnum .46 front needle carb.

FBD.

Sorry, that's nonsense. He probably should replace the plug but that kind of blanket condemnation doesn't wash. I have engines that run great with a Fox long with an idle bar.

His problem is probably with junk in the carb. It could clear itself or he should pull the carb and clean it. Check for loose screws and cracked gaskets or o'rings. No reason it shouldn't run as good as it did when you stored it.

That may be so, Hank....but is one of those engines a K&B 6550 ?

I didn't think so. That's not nonsense either....K&B invented and started
producing K&B 1L plugs for a reason....the reason was their engines. I got
a handfull of those original plugs to try, before K&B had developed the
packaging for them, about 1972 or so.

I learned the hard way, and had it proven to me....that the K&B's don't
like idle bar plugs....they run much, much better on a non idle-bar plug
like the K&B 1L. BTW, I've been running those engines continually most
every weekend for 35 years.

Sorry, that's a fact.

FBD.

Thanks for the plug advice. I need to start making enemies, it seems, in order that I gift them with these plugs.

My carb is the big K&B aluminum "square" design, no ribs. I should have mentioned this.

How should I de-junk and clean the carb? Or where should I get my hands on a Magnum .46 front needle carb? I had considered using a Perry carb and pump for good inverted performance.

With the carb you mention there should be very little possibility of hidden gunk in it. I think the worst problem would be the "O" ring on the low speed needle or the low needle set too lean. All the 6550s being run in this area also do not like the Fox plugs, but prefer the original equipment K&B R/C plugs with idle bar.

Thanks for the info: once I get the old girl running, will a Magnum carb or Perry carb/pump combo make for better time-to-climb or inverted performance?