Wingdinger2

I searched for threads with similar subjects, but after getting impatient, decided I'll just start a new thread. I had a dirty old Magnum 40 GP that I tore apart and crock-potted overnight in antifreeze after removing gaskets and bearings. It did a great job of cleaning it, but after I put it together it absolutely wouldn't run. Turns out the piston was backwards. Anyway, now it runs great except it won't idle without having the glow igniter attached. As soon as the igniter is removed and the engine dropped to idle it dies, right away. Being a relative greenhorn with glow engines, I'm not sure what the problem is. Too rich, too lean on the idle needle? Anyone know what the stock needle settings are?

perdo

My Feedback: (61)

If you left the plug in during the crock pot treatment, put in a new plug. other than that try two turns out on the idle mixture screw, as a starting point.

Campgems

You are to rich on the idle end. That engine has an air bleed carb, so you will want to open up the air bleed screw. Tune the top end first, peak then go rich about 400 RPM. A slight noticeable drop if you don't have a tach. Now open the air screw a 1/4 turn from where you are at and see how that is for a start.

My Mag 40 GP hasn't run for a while, but the carb settings were this, and I don't know if it was running good before it went in the drawer or not. High speed was 1 1/2 turns out from closed. The air bleed was 5 1/4 turns out from closed. That may be a good start point, but as long as you have it running, just turn from where you are at. Open the air bleed about a 1/4 turn at a time until the engine doesn't drop much in RPMwhen you take the glow driver off. When you punch the throttle, it should jump to life. If it stumbles and slowly gains speed, it is to rich on the idle, open up some more, If it just quits when you punch it, it is to lean on the idle close down the air bleed until its running good.

Don

dennis

My Feedback: (90)

good rule of thumb for an airbleed carb is to have the air bleed about 50% uncovered as a starting point and then go from there.
Dennis

PatrickCurry

My Feedback: (20)

Do the RPMs drop significantly when you pull the starter off or will it run strong at top end for a while?  You might try a new glow plug on it just for kicks before you start diddling with your LSN.  I'm with Perdo, if you left the plug in when you put it in the crockpot you might have done something to the element.  

Wingdinger2

It's an engine that I got used, I didn't even try running it before I cleaned it, would probably have been a hopeless case. I did take the glow plug off before cleaning, the plug seems to be good. The engine ran fine from mid to full throttle, but if I yanked the igniter at idle or dropped it to idle after removing it, it promptly quit. I take it the low speed needle is the horizontal one in front, right? That needle is completely blocking the hole, so I think you guys are right. I'm gonna take it out tonight and see what I can do. From what I understand, the low speed needle is the reverse of the high speed needle, right? Turn out to lean, turn in to richen? BTW, what's the other small vertical needle? A throttle stop adjuster?

Wingdinger2

Well, I think I'm making a little progress... I got it to idle some tonight. Still not right though, it keeps on quitting every now and then, but it got too dark to continue. I think it's currently 6 or 6 1/4 turns from closed. Do I just keep on turning it? I took a few recordings with my phone, but I'm not sure how I could post them for you to hear. If you want to listen to them, email me...

PatrickCurry

My Feedback: (20)

Yep, if it was all the way closed it's at the maximum richness.  Opening it up lets more air in and leans out the low end.  Sounds like you're getting close.