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Hello everyone,

First post here.

My Kawasaki FR730V that has started to bog down pretty hard. It runs completely fine when the blades are not engaged. As soon as you engage the blades the motor instantly struggles. When moving through any grass the motor will bog down so hard that it stops. It's like what happens when you try to mow 8" of very thick grass with the deck set at 2" .

I looked around the motor and believe that it is possibly a problem with one of the heads. One of the heads is completely clean and the other one has built up dried oil around the outside seal. I haven't seen any actual oil leaks.

What do you suggest? Should I just buy a completely new (used) set of heads like these a forgot about trying to troubleshoot my existing ones?


Should I attempt to take apart my existing head to see if it is something simple like a gasket? Anything simple I should try before attempting to open up the mower?

Disconnect one plug wire and start engine. Does it start? How does it run?
Disconnect the other plug wire and start it. Does it start? How does it run?
Do you have a dead cylinder?

Well first the seller is not willing to accept returns is a red flag. So you taking a real chance that something wrong with one or both heads. Also you do not reuse those metal head gasket anytime.

Now the complete new cylinder are listed for around $345 ea kit which is for one side and does not come with push rods. #1 is PN 99999-0627 and #2 is PN 99999-0628. They are around $270 off Amazon. So do want to risk getting a bad head assembly of go with a new product?

Well Damn,

I am running on one cylinder. The one from the picture that looks like it has dried oil around the seal won't fire up.

Ready for next test .

Thanks.

Found this bad boy also. This is probably less than what they would charge me at the shop just to do diagnostics .

intrex said:

Well Damn,

I am running on one cylinder. The one from the picture that looks like it has dried oil around the seal won't fire up.

Ready for next test .

Thanks.

Click to expand...

I would
1 check coil for spark
2 remove rocker cover and check valve lash.
3 if equipment available do a leakdown test.
4 if equipment not available remove head and check valves and head gasket.

Thanks Hammer,

Will be testing the spark plugs and coil packs in the morning. Hoping it is one of those since I don't have any means to to a leakdown test.

Right now you are only 1/2 way through the diagnosis .
So you have found out it is only running on 1 cylinder the next step is to find out whu
could be a bad coil a shorted kill wire , a dropped pushrod, bad valve lash etc etc etc

Well,

It looks like this is simply a spark plug failure. I switched the plugs and now the other cylinder is the only one firing.

Headed out to get a new one in a few minutes. I ran this the mower for probably an hour on one cylinder. Do I need to be worried about damage that I may have caused? Should do any kind of extra maintenance knowing that it ran for a while on one cylinder?

Thanks,

No
Get 2 new plugs they are cheap
The mower will probably smoke a bit for an hour or more while accumulated unburned fuel burns off

Kaw sourced plug wires are carbon impregnated string core "wires" and they often don't make good continuity from the plug cable core to the plug cap as they are a crimped connection that has a couple of barbs that are pushed thru the cable sheath into the cable carbon track core. I had exactly the same problem as when I split the cable there was only a carbon track and no string for about 1" from the end and the barbs had bent over not reaching the center of the spark cable core. Replaced both sides with these....

NGK (8328) LB01EP Spark Plug Cap

They have a screw in the cable end of the cap that runs up into the plug cable making a more positive connection. Not saying this is what your problem is but sounds a lot like a spark issue under load.

And the problem with Kaw replacement coils is the cable comes already attached and molded into the coil. I've got two brand new coils on my shelves before I figured out what was really going on.