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Starting problems and What compression?

#1

D

dkslucas

I have an old Cub Cadet RZT 50 with a Kawasaki FH661V that I am having problems starting. I have again rebuilt the carb, have spark, and it continues to seem to flood and not be able to start. I checked the compression and it is 90 in both cylinders which seems low to me, but the service manual says anything over 57 ( which seems way way too low!) is fine. I adjusted the valves that were a little too tight. Any suggestions? Should I attempt new rings to up the compression? Thanks.


#2

D

dkslucas

Update - I hadn't rechecked the compression after adjusting the valves and now the compression is up to 150 per cylinder. So no problems there.


#3

D

Deerlane

Fuel solenoid working?


#4

D

dkslucas

yes, there is fuel in the carb, the spark plugs are wet with gas. I pulled the heads and one head and cylinder have lots of carbon build up and the other very little. On the head/cylinder with more carbon the exhaust valve is more brown and not black like on the other head. Does that mean anything? It had been backfiring quite a bit as well. Thanks for the help.
Dave


#5

D

Deerlane

Sounds like you need to do a leak down test. Remove spark plug and put cyl on TDC (Perfect TDC) on the compression stroke. If you can add no more than 10 lbs of air to the TDC cyl and listen at the oil fill cap, carb and exh.
Are you sure fuel is ok and fuel solenoid is working proper.
I know this may sound odd, But I have seen it in large engine. Is the flywheel key broke. ( out of time)
There is diodes in the wire harness between the two ignition modules. This can make the coils do things to make it out of time.
The engine should run on one cyl even if one is damage, but your engine will not run at all?

I like this kind of diagnose. They are like trick questions. LOL


#6

D

dkslucas

I now have pulled the heads so the pressure test will have to wait, but the flywheel key being broken makes sense because it seems like a timing issue, but since there isn't anyway to adjust the timing I didn't consider that - to get to the flywheel key I assume I just need to pull the flywheel? Thanks for the help.


#7

D

Deerlane

When you said (It had been backfiring quite a bit as well) That was the clue!

I have done the same thing as you too. Take it apart, pull all my hair out and then find a 1 DOLLOR BROKEN KEY. LOL


#8

D

dkslucas

I will pull the flywheel and let you know. thanks for the help.


#9

D

dkslucas

Well it wasn't any of the things previously mentioned! I pulled flywheel and the key was fine, pulled heads, cleaned all the carbon off heads and pistons, put all back together and nothing! I checked the sparks, which I had done previously (actually the first thing I do) and the number one cylinder now had no spark! I switched the wires from no 2 to no 1 and still nothing. Purchased a new coil and now it runs like a champ! So I guess the coil was intermittently firing before and for whatever reason it totally went out and made the diagnosis simple. Thanks for the input.


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