Generator surging backfiring

[Shooter]

My generator ( Kohler 5kw, 2003 model) is not running properly. It is surging and backfiring regardless of whether it is under load or not.

I have a theory that I want to test with you on the forum. Here goes:

My generator water pump does not seem to be pumping consistently. Sometimes normal, sometimes not at all ( for very short times ) I cant tell if the change in water flow is the result of the generator surging, or the surging is a result of erratic water flow.

The water flow issue was the first one I noticed. My theory is that if the cooling system and exhaust are not seeing a consistent flow of cooling water, the engine would see inconsistent backpressure from the exhaust. My theory is this would induce the poor performance.

Does this theory hold water, or am I all wet? I think either way I need to replace the water pump. If I'm all wet, what else should I be looking at?

Thanks all.

Best regards

Shooter

 

[Torque]

I'd start with plugs. I've noticed my Kohler is really fussy about plugs and goes through them fairly quickly. I've had similar symptoms (in terms of the engine's performance, not the water issue) and fixed it with plugs. Also, check your gap, I've found the plugs that go in the Kohler can come with the gaps way off....

I don't think backpressure could be making much of an issue unless you have some type of obstruction. Anything at or below stock should allow it to run just fine. Obviously you want the appropriate amount but I'd be more concerned with too much than too little as long as you're getting water. If you have not done the impeller recently, I'd do it.

 

[Bugsy24]

You might have multiple problems, I'd also check your Impeller!!!!

 

[Shooter]

I'd start with plugs. I've noticed my Kohler is really fussy about plugs and goes through them fairly quickly. I've had similar symptoms (in terms of the engine's performance, not the water issue) and fixed it with plugs. Also, check your gap, I've found the plugs that go in the Kohler can come with the gaps way off....

I don't think backpressure could be making much of an issue unless you have some type of obstruction. Anything at or below stock should allow it to run just fine. Obviously you want the appropriate amount but I'd be more concerned with too much than too little as long as you're getting water. If you have not done the impeller recently, I'd do it.

Thanks. Do you happen to know what plug it takes? I can't get in to check cause of an injury.

Best

Shooter

 

[Bugsy24]

Do a search for Kohler and there was a recent thread about someone speaking to Kohler and they upgrade to a different Plug Size!!

 

[MonacoMike]

As Marshall suggested look for the thread, search for spark plugs. There was a suggestion for a hotter plug for this situation that I added to my emergency kit. MM

 

[Torque]

Re: Kohler 5E spark plug cross reference?
"Not sure exactly the model year you have but I use GM46180=NGK BPR4ES=Champion RN14YC. I get the NGK's at the local auto parts store for $1.63 each. Some people use the next hotter plug (e.g. BPR6ES)"

This is what I found after searching the other threads. Now I'm curious what I put in mine last and which heat range it is. What I do know is I found the Kohler manual and the Kawasaki Manual that came with my packet to both have very different gap requirements. The plugs I bought did not match either the Kawi or Kohler suggestion, nor did their gaps match one another. Hope this helps. I'll re-post what I ended up using if that helps.

My search also gave me some good info on the water ingestion issues I did not know about......... This forum has very good info!