Trouble Starting 4 Cyl Hercules Gas Engine

[Reckless]

I'm having trouble starting my 4 cyl gas engine. It's turning over fine, but won't fire. I don't seem to be getting spark and I'm not to sure about the magneto. I have been over the TMs multiple times now and still get nothing. Any help would be appreciated!

 

[MWMULES]

Which 4 cyl Hercules engine, there are several.

 

[Reckless]

4a084

 

[Keith_J]

No spark means magneto. Too complex to describe here, the TMs do a good job. Saturn Surplus has the magnetos if you don't feel like setting point gap and dwell. Careful, they will shock the fool out of you.

 

[Reckless]

I'll check back in the TMs. Would it be better to buy the entire magneto assembly with leads for $120 or just the inner cap and rotor for $25?

 

[PeterD]

I'll check back in the TMs. Would it be better to buy the entire magneto assembly with leads for $120 or just the inner cap and rotor for $25?

Just my opinion: I'd buy the entire unit and then I'd save the original for spare parts. I do have a lot of storage space, however.

 

[Keith_J]

Easiest to replace the whole magneto rather than mess around replacing parts since you have not diagnosed what the problem is. Is it an impulse magneto or a straight driven? Fairbanks Morse or Slick?

 

[rustystud]

Magneto's have condensers in them just like the old point systems do. I would replace that first before you condemn the whole mag.

 

[61sleepercab]

Bad condenser or dirty points will kill a magneto deader than a door nail. Get a points file, a sandpaper finger nail buffer stick or non silicon carbide sandpaper (black or grey silicon carbide paper leaves a film on electrical contacts) 220 or 300 grit and clean and shine up points and then take thin card board or stiff paper and pull through closed points to remove grit.Check and Set points gap if it changed. You can use a meter to check condenser and whether you have good contact between both sides of the points. I have seen a hot mag throw blue fire 3/4 of an inch from spark plug wire to ground and the engine never missed a beat. Do not hold on to the plug wire like a mower engine to check fire or you will learn never to do that again. If your engine has a impulse drive coupler that snaps when cranking at low speed it must work or you will not get good fire. A bad plug can fire out of the engine but fail under compression when installed. Good luck ,try a clean up before you throw a mag into the has been pile. Mark

 

[Reckless]

I'll pull it off tonight, check on it and report back. Thanks for the input fellas!

 

[rustystud]

Bad condenser or dirty points will kill a magneto deader than a door nail. Get a points file, a sandpaper finger nail buffer stick or non silicon carbide sandpaper (black or grey silicon carbide paper leaves a film on electrical contacts) 220 or 300 grit and clean and shine up points and then take thin card board or stiff paper and pull through closed points to remove grit.Check and Set points gap if it changed. You can use a meter to check condenser and whether you have good contact between both sides of the points. I have seen a hot mag throw blue fire 3/4 of an inch from spark plug wire to ground and the engine never missed a beat. Do not hold on to the plug wire like a mower engine to check fire or you will learn never to do that again. If your engine has a impulse drive coupler that snaps when cranking at low speed it must work or you will not get good fire. A bad plug can fire out of the engine but fail under compression when installed. Good luck ,try a clean up before you throw a mag into the has been pile. Mark

Yep, what he said !