Mr J. Smit

[JANSMIT]

I own a Jonn Deere lawn mower, type F510. Product info: MOF 510A150332, engine Kawasaki PA 420A-BS02, eng. nr. PA420A009649.
Problem: the engine starts very difficult and when running will not accelerate at all and backfires continiously with blue flames in the carburettor. The coil and the ignitor were already replaced without any result.
The carburettor is spic and span and there is no water in the fuel.
Compression is o.k, +/- 7 bar.
When the motor is running, manual activation of the choke and throttle valve have no influence on the engines behaviour.
The spark is provided by the coil only, because the moment the ignitor is connected the engines dies.

Regards/ J. Smit

 

[Mike_Goad]

I own a Jonn Deere lawn mower, type F510. Product info: MOF 510A150332, engine Kawasaki PA 420A-BS02, eng. nr. PA420A009649.
Problem: the engine starts very difficult and when running will not accelerate at all and backfires continiously with blue flames in the carburettor. The coil and the ignitor were already replaced without any result.
The carburettor is spic and span and there is no water in the fuel.
Compression is o.k, +/- 7 bar.
When the motor is running, manual activation of the choke and throttle valve have no influence on the engines behaviour.
The spark is provided by the coil only, because the moment the ignitor is connected the engines dies.

Regards/ J. Smit

I am confused, when the igniter is "connected" the engine dies? This in itself is an issue as the igniter on these engines were basically an electronic set of points. it tells the engine when to fire the plug.
as far as flames in the carburetor, this is a timing issue. it is either the igniter, flywheel key, or valve timing. it could also be that the intake valve is not sealing but you said that the pressure was good.

 

[JANSMIT]

I am confused, when the igniter is "connected" the engine dies? This in itself is an issue as the igniter on these engines were basically an electronic set of points. it tells the engine when to fire the plug.
as far as flames in the carburetor, this is a timing issue. it is either the igniter, flywheel key, or valve timing. it could also be that the intake valve is not sealing but you said that the pressure was good.

Mike: Sorry, my fault. The "engine dies when connecting the ignitor" is incorrect. I did not realize that the new coil which i have installed, already has an integrated ignitor. No wonder that when I connected the standard separate ignitor the engine dies.
However the problem remains; I checked the valve timing by taking the engine apart and making sure that the marks on the cranckshaft gear and camshaft gear are in the correct position.
The flywheel key was inspected this afternoon and appears to be o.k.
Could it be that the new coil with the integrated ignitor, which is not standard for this type of Kawasaki engine, causes the described problem?

Kind regards/ Jan Smit

 

[Mike_Goad]

Mike: Sorry, my fault. The "engine dies when connecting the ignitor" is incorrect. I did not realize that the new coil which i have installed, already has an integrated ignitor. No wonder that when I connected the standard separate ignitor the engine dies.
However the problem remains; I checked the valve timing by taking the engine apart and making sure that the marks on the cranckshaft gear and camshaft gear are in the correct position.
The flywheel key was inspected this afternoon and appears to be o.k.
Could it be that the new coil with the integrated ignitor, which is not standard for this type of Kawasaki engine, causes the described problem?

Kind regards/ Jan Smit

absolutely. I am not aware of an integrated coil for the 420 engine. this has always had a separate coil and igniter. if the coil is after market, this could be the issue. That seems to be what everything is boiling down to.

 

[motoman]

The fact that you get no change when the manual choke is operated suggests that the choke fuel passageway (hole, orifice) is plugged. That ,in turn , suggests that the carburetor may be gummed despite looking clean to you. Use the search function to sample the numerous posts on cleaning carburetors.

 

[JANSMIT]

absolutely. I am not aware of an integrated coil for the 420 engine. this has always had a separate coil and igniter. if the coil is after market, this could be the issue. That seems to be what everything is boiling down to.

Sorry for my delayed reaction.

It finally became clear that my dealer, ( official John Deere), had just grabbed A coil from the shelve. After changing the coil for one with the correct part number and after having changed the ignitor for an aftermarket one, (US $ 12.50), the engine starts without delay and accelerates perfectly.
By the way, I have tried to download a F510 electrical diagram from the internet, without succes. Would you have one?

Thanks in advance/ Jan Smit

 

[Michael_G]

Sorry for the late reply. my password got messed up and the site would not send me a new password so i had to create a new persona.
i could not find a website that would allow you to download a free service manual but i did see a couple where you could get one for $5.
verify which engine you have. i am thinking that you have the FC420v. John Deere may give it a different designation but as long as it says 420, then it is a FC420v