420cc Honda clone (190F) generator engine always kicks back when trying to start

[Eejay]

This started happening randomly, initially it would kickback 2-4 times before it would eventually turn over and start running, but it ran rough and hot, and started dieseling when shut down

However, after giving it a shim head gasket to bump up compression (because I planned on running it on propane only) it would never stop kicking back and i cant get it to start.

I've replaced the magneto coil, spark plug, ignition/starter switch, crankshaft (due to potential gear slip on the shaft), and camshaft, to no result.

I've checked the valve lash, the timing key, and magneto coil lash, and they are all good.

I've tried retarding the ignition timing using a custom timing key, and adjusting the air/fuel ratio to no result.

It's behaving as if it has a massive ignition timing advance, with the kickback and the past rough running, overheating, and dieseling. Despite having a stock timing key, coil, and flywheel.

 

[pomfish]

So put the stock thickness head gasket back on maybe?

 

[Eejay]

So put the stock thickness head gasket back on maybe?

With the stock gasket on it, it still kicks, but can get it started after enough trying, however it runs terribly anyways.

I plan on bumping up the horsepower up to run it on a higher load generator using propane, which is why i bumped up the compression using a shim gasket.

 

[SAS289]

You're not running real old fuel are you? Have you tried running it on propane?

Hope you get it going. They run nice on propane. My 208 Ducar sounds quieter and handles loads just as well as gasoline.

 

[Eejay]

You're not running real old fuel are you? Have you tried running it on propane?

Hope you get it going. They run nice on propane. My 208 Ducar sounds quieter and handles loads just as well as gasoline.

Yeah I'm trying to get it started using propane and starting fluid

 

[sparkwizard]

Does it kick back even with the electric starter?
Why did it overheat?????? At what point in this process did you change the cam? What cam is in it now? Does your current cam have a proper, working compression release?

 

[Eejay]

Does it kick back even with the electric starter?
Why did it overheat?????? At what point in this process did you change the cam? What cam is in it now? Does your current cam have a proper, working compression release?

Yes it kicks back with the electric starter.

It could be overheating because of something to do with the ignition system, I know it's not lean burning because i made sure the carb was jetted correctly (back when i ran it normally on gas, FYI it was overheating when running on gas).

I changed the cam after I checked the valve lash, changed the spark plug and coil, and checked the coil lash

The new cam is an extended duration cam with stock lift (it made no difference after adding it).

Yes the new cam has a working compression release.

 

[sparkwizard]

Take the plug wire off of the plug and see if it kicks back while cranking. If it does, you do not have an ignition problem. if it only kicks back with the plug wire hooked up, look at the ignition system.
Your initial post was confusing. Did it overheat new? Did it overheat before you did any work to it? Did it ever run correctly?

 

[hermans13]

Sparkwizard, I'm not familiar with this engine, when replacing the coil does it have to be set like a Tecumseh?

 

[Eejay]

Take the plug wire off of the plug and see if it kicks back while cranking. If it does, you do not have an ignition problem. if it only kicks back with the plug wire hooked up, look at the ignition system.
Your initial post was confusing. Did it overheat new? Did it overheat before you did any work to it? Did it ever run correctly?

It did run correctly when I bought it.

I bought it used so I have no idea if it had any problems before hand.

way before it started overheating and having problems I had to replace the valves and valve retainers because they were worn and the valve dropped with no damage caused.

 

[sparkwizard]

Sparkwizard, I'm not familiar with this engine, when replacing the coil does it have to be set like a Tecumseh?

Coil gap needs to be set like a Predator or a Tecumseh with the coil on the outside of the flywheel.(electronic ignition, no points.)
If the coil is inside the flywheel on the Tec, there is usually not a coil gap adjustment, only a POINT gap adjustment.

 

[sparkwizard]

It did run correctly when I bought it.

I bought it used so I have no idea if it had any problems before hand.

way before it started overheating and having problems I had to replace the valves and valve retainers because they were worn and the valve dropped with no damage caused.

I am sure you know you did not answer my question.
It ran correctly when you bought it. It did not overheat or have problems before you changed the valve and retainers.
Are we getting somewhere, now?

 

[sparkwizard]

OK, sorry, how long after you replaced the valves and guides, did the overheating, running badly and overheating start?
Did you mill, sand, file or swap the head while you had it apart?
How are you adjusting your fuel ratio? Is the stock carb still there?
Did it drop a valve while running? Did it ever run correctly, after that?

 

[sparkwizard]

I want to go back to when it started to overheat and find out why, because that indicates a real problem on a fan forced air cooled engine.
Running hot and dieseling are not normal unless someone raises compression and leans the fuel mixture, or does stupid stuff, like remove the fan, remove the shroud or plug up the fins with BS.

 

[sparkwizard]

You kept referring to ignition timing. I doubt your problem is timing unless you worked on it and somehow neglected to mention that.
In order to put that theory to bed, disconnect the plug wire and crank the engine.
Does it crank with the spark plug disconnected?