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Randall, RVIA Certification
Category: RV
Satisfied Customers: 11682
Experience:  RVDA/RVIA Master Certified Technician with many years experience.
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It is backfiring but idle goes up and down and also its loss

Customer Question

It is backfiring but idle goes up and down and also its loss of power it won't take a load
JA: Where exactly do you think the noise is coming from? And how long has this been going on?
Customer: The fluctuating of the idle and loss of power under a load
JA: What is the model/year of your RV?
Customer: It's a Kohler generator that I'm talking about in my RV
JA: What year is your RV?
Customer: 91
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: Yes it's been having problems since then yes plan on doing it my self
JA: Anything else you think the mechanic should know?
Customer: Yeah I was like 1800 hours and only one tune up
Submitted: 1 year ago.
Category: RV
Expert:  Randall replied 1 year ago.

What is the complete model number off this genset? Please get back to me with this information and I will try to help you sort this out.

Customer: replied 1 year ago.
Serial# *****
Spec# *****
Model# *****
SPEC# *****
SERIAL#(###) ###-####
It pops and fluctuates with no load non stop. It dies with a load it backfires sometimes when turning it off. Its hard to start. New air filter plugs and points but the plugs have already been cleaned with a torch a couple times the points have already had oil on them from the screws not screwed in when running. And hard to get to. The fuel, idle fuel screws have been messed with and not sue the timing is right
Expert:  Randall replied 1 year ago.

Do you have a copy of the Service Manual or not?

Expert:  Randall replied 1 year ago.

Did you check the valve clearance? Valves that are too tight can do this.

Expert:  Randall replied 1 year ago.

I am adding a link to the Kohler Service Manual which covers this set. Print this out so you have it. See the trouble shooting section. Be sure that the fuel in the system is fresh and has some additive in there like Stabil. Today's gas goes bad very quickly. Check the obvious things first, like the timing and filters and valve lash. The carb may need a good cleaning. Use lacquer thinner and some compressed air to blow out the jets and orifices. Please get backl to me if you need more. All follow ups are included in our fee.

Customer: replied 1 year ago.
Where is the link to go to
Expert:  Randall replied 1 year ago.

Sorry about that...........forgot to hit the button!

Customer: replied 1 year ago.
Is this for the 4.5CKM21-RV?
Expert:  Randall replied 1 year ago.

If you look at the cover it is for quite a few different sets. The major differences are just in the ouput in watts or whether the genset is putting out 120 or 240 on the voltage. The engine trouble shooting is about the same on most of these.

Expert:  Randall replied 1 year ago.

If you go to this site that I have added a link for they can supply you with one for just this set that may be more complete.

Expert:  Randall replied 1 year ago.

Just checking back in to see if you were able to resolve this issue or do you still need some additional input from me here?

Customer: replied 1 year ago.
just later
Expert:  Randall replied 1 year ago.

O.K........get back to me when you are ready.