My Kubota mower would die and be hard to restart. I finally took it to the dealer. It’s 7 years old and only has 47 hours on it. They ran it until it died and couldn’t restart. Did compression test and said 75psi on one side and 81psi on the other side. Recommended replacing the engine. ??? Any idea why the engine went bad at 47 hours? Where is the best place to get replacement engines? Thanks in advance
FR651v low compression
- Thread starter Papalote
- Start date
Before doing anything I would have the dealer preform a leak down test on each cylinder. This will give you a better idea as to where the problem exists and how to proceed. A dealer who just does a compression test and then says “replace “ is a little suspect in my eyes. Might have to go to a different dealer., which I would recommend. May be less costly in the long run. Never heard of a junk Kawasaki after -50 hours.
There is nothing wrong with the compression. It is above the minimum requirement. There are many things it could be but a replacement engine it is not. Most mechanics these days only know how to replace. They haven’t been taught to test.
I agree with both of y’all. I don’t think they could figure out what is wrong so replace is the easy way out. There aren’t any other dealers close. This dealer is mostly an equipment dealer. Thanks for the info and advice. When I get it home I’ll do a compression test when it’s cold. I think it’s a fuel issue myself.
sgkent
Lawn Addict
the basic when a gasoline engine will not start is to figure which of the three items is missing.
Fuel and air in a fairly broad ratio
Spark
Compression
You've already ruled out compression. If that engine has a compression release, 75 to 81 psi is fine. If it does not, it is low but it would still run.
Lack of spark would require both cylinders to lose spark. That means something common like an ignition switch over heating, or a safety switch misbehaving, like an oil level sensor. But checking for spark is rather easy with either a spark tester or a timing light.
Fuel problems come in three flavors. They are: not enough, too much, or bad fuel/water in fuel. If it is too much you would smell it. If it is not enough you can spray some Berryman's B12 into the carb, or squirt a teaspoon of gasoline into the carb. If it runs for a few seconds then you can try to figure why there is a defect in the fuel system.
There can be another cause which is not really common but it does happen. The exhaust gets plugged by mud daubers, or mice that move in and nest over winter. Normally an engine like that will run for 30 seconds to a minute then crap out.
Fuel and air in a fairly broad ratio
Spark
Compression
You've already ruled out compression. If that engine has a compression release, 75 to 81 psi is fine. If it does not, it is low but it would still run.
Lack of spark would require both cylinders to lose spark. That means something common like an ignition switch over heating, or a safety switch misbehaving, like an oil level sensor. But checking for spark is rather easy with either a spark tester or a timing light.
Fuel problems come in three flavors. They are: not enough, too much, or bad fuel/water in fuel. If it is too much you would smell it. If it is not enough you can spray some Berryman's B12 into the carb, or squirt a teaspoon of gasoline into the carb. If it runs for a few seconds then you can try to figure why there is a defect in the fuel system.
There can be another cause which is not really common but it does happen. The exhaust gets plugged by mud daubers, or mice that move in and nest over winter. Normally an engine like that will run for 30 seconds to a minute then crap out.
StarTech
Lawn Royalty
Most Kawasaki engines have an ACR (automatic compression release) which make testing compression useless.
Personally I would get a second opinion locally. That one of my did with a Scag mower that the dealer said the engine was and want $4K just for an engine. The brought it to me for a second opinion and all it was a blown head gasket. Now that engine was consuming lots of oil but ran very strong cutting overgrown grass.
Personally I would get a second opinion locally. That one of my did with a Scag mower that the dealer said the engine was and want $4K just for an engine. The brought it to me for a second opinion and all it was a blown head gasket. Now that engine was consuming lots of oil but ran very strong cutting overgrown grass.
Useless? That makes zero sense. Kawasaki’s minimum compression spec is with the ACR taken into consideration.
You need to have a leakdown test to diagnose the problem. I understand you may not have a good repair shop locally, but going out of your area maybe less costly than replacing the engine. If you are going to try to do it yourself, some auto parts places loan out testers, but you have to know how to use them to get accurate information. Might talk to your neighbors or friends and see if they know of a retired old timer who would be willing and help.
Don't overlook the Valve lash! The valve lash will change slightly from when the engine is cold vs when it heats up (like it is 100 in NC now). If the tolerance is not correctly set, you may have a valve that is not closing all the way to the seat. Check your TDC Valve lash on the ignition stroke before doing anything else.
FYI, I just watched a YT video where the same thing happened with a Kohler. When it got hot, it would stall and not restart, adjusted valves and all was ok. Worth a shot and it is worth some time and checking how to adjust online. Good luck, you got this!
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