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Kawasaki Automatic compression release

#1

H

HNewmans

I have had an ongoing problem with the automatic compression release on my Cub Cadet RZT 50 for 6 years now. I did not know what the problem was until this last year. I just knew that none of the factory starters would turn my engine over without lots of playing with the starter, jumping off with a truck battery etc. I took my unit to the dealer 4 or 5 times but they never found the problem. I gave up on them years ago. I had 6 years of warranty but I thought about the definition of crazy " Doing the same thing over and over and expecting different results". Hence I quit taking the unit to the dealer. A few months ago I read an article where a man stated that he had the same problem and discovered it was a faulty automatic compression release. I did not know the unit had one, otherwise I would have specifically told the dealer about it. After I found out I called the dealer and they said to bring it in and they would change out the camshaft. On my dime, of course, because my 6 years of warranty are now expired. I griped and moaned to no avail that they never found the problem years previously. They said they had a service department issue back then but, it is OK now. I have replaced the starter 3 times over the years, and it needs changing again now. It burns up with me repetitively hitting it with 500+ amps to start it. I have changed the starter solenoid to an automotive version and changed the wiring from the battery to the solenoid and to the starter to 4 gauge stranded because the factory wire would burn out in a heart beat. How do you spell frustration????? Am I the only person who has ever had this problem???


#2

H

HNewmans

HNewmans said:
I have had an ongoing problem with the automatic compression release on my Cub Cadet RZT 50 for 6 years now. I did not know what the problem was until this last year. I just knew that none of the factory starters would turn my engine over without lots of playing with the starter, jumping off with a truck battery etc. I took my unit to the dealer 4 or 5 times but they never found the problem. I gave up on them years ago. I had 6 years of warranty but I thought about the definition of crazy " Doing the same thing over and over and expecting different results". Hence I quit taking the unit to the dealer. A few months ago I read an article where a man stated that he had the same problem and discovered it was a faulty automatic compression release. I did not know the unit had one, otherwise I would have specifically told the dealer about it. After I found out I called the dealer and they said to bring it in and they would change out the camshaft. On my dime, of course, because my 6 years of warranty are now expired. I griped and moaned to no avail that they never found the problem years previously. They said they had a service department issue back then but, it is OK now. I have replaced the starter 3 times over the years, and it needs changing again now. It burns up with me repetitively hitting it with 500+ amps to start it. I have changed the starter solenoid to an automotive version and changed the wiring from the battery to the solenoid and to the starter to 4 gauge stranded because the factory wire would burn out in a heart beat. How do you spell frustration????? Am I the only person who has ever had this problem???
Click to expand...
The specific motor is a FR651V-AS04.


#3

7394

7394

That's the Kaw engine I have in my Zero, The Comp releases are built into the cam lobes, at cranking speed, it bleeds off compression for easy engine spinning.

I'm surprised your dealer told you they did not know about this. This engine has been in continuous production for many, many years (at least).


#4

cpurvis

cpurvis

You can see this if you take off the valve covers and turn the engine over by hand. The exhaust valve will have a very short duration, very small lift 'bump' opening prior to the normal opening.

The valve lash is typically only .004" to .006" on these engines. Too much valve lash (and it doesn't take much) will cause the exhaust valve to not do its 'bump' opening, thus rendering the compression release inoperative.

First thing to check in your situation is the valve clearances.


#5

7394

7394

Specs I have from Kaw online Repair manual for valve lash are: Intake, Exhaust = 0.0020 ∼ 0.0039 in.


#6

cpurvis

cpurvis

All I have seen are .1mm to .15mm which translates to .004" to .006".


#7

7394

7394

Cut-n-pasted right outta the book. 0.05 ∼ 0.10 mm (0.0020 ∼ 0.0039 in.)


#8

cpurvis

cpurvis

From p.64 of this link: https://www.manualslib.com/manual/856622/Kawasaki-Fh451v.html?page=64#manual

.1mm to .15mm The five V-twin models listed in this manual use this clearance.

Not saying this applies to ALL Kawasaki engines; just the ones I've come into contact with.


#9

7394

7394

Totally different engines, according to your link. OP & my Kaw are the FR651V engines, including

FR651V, FR691V, FR730V

FS651V, FS691V, FS730V
FX651V, FX691V, FX730V


#10

cpurvis

cpurvis

Then it pays to set the valve clearance per the specification for the particular model you have. We've established there are at least two different sets of valve clearances; there may be more.


#11

7394

7394

Seems so, I also found my engine in your link at the bottom & double checked the valve lash spec. Thanks for the link. :thumbsup:


#12

W

WVZR-1

I have a FR651V with similar problem "as described" by the OP. I bought this mower and was told it needed an engine but it nearly always cranks and starts. Often just a click and the starter pinion is hung in the flywheel. I did a new starter from what's generally mentioned as a responsible reseller and the issue doesn't change. This mower when running, runs well with no issues. I've mowed maybe 4+ hours with it and start it occasionally just for grins. I keep the upper cover very easy to remove so that if the pinion sticks it's a very easy turn and the pinion drops. I'd say it cranks and runs 90%+ of the time. I've considered a sale but I'd like to either fix or make the buyer aware of what the real issue is.

Has anyone replaced the camshaft in any of the FR/FS vertical engines that are similarly configured. Compression is good and the valves I checked at .002 & .004, feeler was near snug . The mower doesn't appear to have many hours. Shops in the area don't seem real well versed with anything other than more easily diagnosed issues. They don't want to talk about camshaft replacement.

Battery is 12.4+ and maybe 18 moths old.

OP - did the larger gauge cable actually help?


#13

B

bertsmobile1

Heavier cables always help and take a ground either directly to one of the starter mounting bolts or to an extended engine mounting bolt with a nut in the top.
The ground connection can be a big problem.
If the starter gear sticks on the flywheel then pop a metal shim under the starter to space it out a little .
You can also run a disc on the top & bottom of the flywheel gears as occasionally you get little burs on the teeth.


#14

7394

7394

WVZR-1- My FR651V Owners Manual states the valves lash to be .004~.006

That link has incorrect info on valve lash.


#15

W

WVZR-1

7394 said:
WVZR-1- My FR651V Owners Manual states the valves lash to be .004~.006

That link has incorrect info on valve lash.
Click to expand...

I mistook you as the OP from page 1 and PM'd you in error. The OP hasn't returned to the thread. It would be interesting if maybe he did. I've had ACR thoughts for months but dealers ain't interested in conversations. Most seem to only be interested in external parts replacements OR complete engine purchases.

I don't see that specification in any of the FR/FS/FX 651/691 engine specification manuals from Kawasaki. I haven't used/checked any link just the FSM from Kawasaki.

Twice previously you've mentioned .0002 ~.00039 and that's what I see everywhere. The Automatic Compression Release interests me most maybe and potentially a camshaft replacement.

The OP mentioned he'd done larger cables, automotive grade solenoid and it hadn't actually done much for him as years later he's into a 3d starter and the same issue. I'll think harder maybe and consider that. Considering the length of the cables I couldn't convince myself that larger cable could be an improvement.

Does anyone have a blown FR651V hanging around? An FS maybe?


#16

7394

7394

7394 said:
Cut-n-pasted right outta the book. 0.05 ∼ 0.10 mm (0.0020 ∼ 0.0039 in.)
Click to expand...

This is INCORRECT info, according to Kawasaki & my Owners Manual state the FR651V valve lash is .004~.006

Sorry for posting the wrong info, I got that from a link posted here.

WVZR-1- No problem, many times someone posts a question & later never returns. That's life.


#17

W

wgf

I have a Kawasaki FH730V with 600 hours, and it's had a problem with hot restart, i.e., it would not start when the engine is hot - had to wait a couple hours until engine cooled (however it would restart while hot IF I CONNECTED A BATTERY CHARGER TO BATTERY).
Based on various comments I saw in this thread, I checked the valve lash. One was 0.016" and the other three were 0.020". I set all to 0.004" and EUREKA, the restart problem was solved.
Apparently the excessive valve lash caused the compression release to be ineffective. Morale is: follow Kawasaki's maintenance recommendation to check the valve lash at 300 hour intervals.


#18

7394

7394

That engine didn't sound like a sewing machine with lash so extremely wide ?


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