Cub Cadet 54" RZT - Kawasaki FR691V - idle bouning?

Integraoligist

LawnSite Member
Hi all,

I have a 2 year old Cub Cadet 54" RZT - Kawasaki FR691V engine, never had an issue with the engine before now... the crap cutting quality is another story.

For whatever reason now while it's running and sitting at idle, the rpms drop and raise to normal then drop and raise and drop and raise... but when I put a load on it either by pressing the gas to move or put the blades on, it runs fine again.

I double checked the oil (which the oil and filter were replaced about 5 runtime hours ago) & the air filter is clean.

I've not replaced the plugs yet, but in my experience the plugs are usually only an issue if it's bogging when you put a load on a motor.

The gas filter looks clean...

What else could the issue be?

Thanks all!
 

Integrity-LC

LawnSite Member
Location
West Michigan
In my experience surging is usually a carb issue. In most cases a plugged jet or port.
 
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Integraoligist

LawnSite Member
I don't know if it's considered Surging... the idle is not going higher then normal. It's going lower, almost dying then back to normal over and over when there is no load. If there is a load, it runs normally.
 

flintknapper

LawnSite Senior Member
How many hours on the engine?

What you describe is indeed 'surging' *defined as an up and down change in rpm*.

Generally carb related but if there is a 'miss' attendant with the surging....then you might check your valve lash. If your valve lash is excessive *or too tight for that matter* idle speed will suffer and the governor is trying to 'save' the engine from dying. But at higher speeds will operate OK.

I'd be looking at the carb first though.
 
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Integraoligist

LawnSite Member
Just over 100h on the mower.

Forgot to mention that while it's surging it sometimes backfires as well now.
I'll try cleaning the carb out and see where it goes from there.

Thanks guys!
 

Breezmeister

LawnSite Gold Member
Location
South Jersey
Just over 100h on the mower.
Forgot to mention that while it's surging it sometimes backfires as well now.

Muffler loading up on gas.......
Sounds like you have a missing welch plug(s). It's an easy fix and a common problem with Kaws. If they are missing, see pic, you can get them from your dealer.

Image2.jpg
 
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Integraoligist

LawnSite Member
Interesting, I'll check those in the morning. thanks!
If they are missing, do I need to remove and clean the carb? Or just pop new welch plugs back in... maybe with a little red loctite? and call it a day.
 

Breezmeister

LawnSite Gold Member
Location
South Jersey
do I need to remove and clean the carb? Or just pop new welch plugs back in... maybe with a little red loctite?


Red Loctite will work and if you read the many different post about this in here, finger nail polish, enamel paint and super glue and more. As for cleaning the carb, if it solves your problem, no.
.
 

Breezmeister

LawnSite Gold Member
Location
South Jersey

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