1989 Force 50hp spark plug options

Sdistad

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Jun 29, 2022
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My engine was running a bit "squirrely" so I changed the plugs to the ones it called for (at least the ones that crossed referenced for it) and now it runs but barely enough to make a wake. The ones I removed were NGK BP8H-N - gapped plugs - and the new ones are NGK BUHX with no gap. Any suggestions?
 

jerryjerry05

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May 7, 2008
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Champion UL-18V or the NGK equal NGK BUHX; NGK stk 2522
Either of these should work.
Explain the problem??

Do a compression and a spark test. Post the results.
The 50 can run on 1 cyl. not great but can run.
 

racerone

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Dec 28, 2013
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37,819
There may be more things wrong with this engine.-----Post the compression test numbers.-----Any other trouble shooting done ?-----Water pump impeller changed recently or never ?-----Checked for water in the fuel ?----Flywheel key checked ?-----Might be running on just 1 cylinder !
 

Sdistad

Cadet
Joined
Jun 29, 2022
Messages
7
Champion UL-18V or the NGK equal NGK BUHX; NGK stk 2522
Either of these should work.
Explain the problem??

Do a compression and a spark test. Post the results.
The 50 can run on 1 cyl. not great but can run.
Did a spark test today and, using an in-line tester, got a yellow spark on one cylinder and a red/purple on the other. New coil packs? They are the blue ones. Not sure where to find them. I'll do the compression test tomorrow.
 

jerryjerry05

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May 7, 2008
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18,037
Hook a spark plug to the first lead. Ground it to the block and turn it over.
Then do the same to the other lead and compare the sparks.
Any difference? change the coils around and see if the bad spark follows the change??
Ebay usually has packs/coils.

http://standardmagneto.com/Parts.html these people sell new and real good prices.
 

racerone

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Dec 28, 2013
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37,819
Use a proper spark testing device.---Easy to make with wire and piece of wood , stick , tape at home.----Spark on a good system should jump a gap of 3/8" or more.
 

Sdistad

Cadet
Joined
Jun 29, 2022
Messages
7
Hook a spark plug to the first lead. Ground it to the block and turn it over.
Then do the same to the other lead and compare the sparks.
Any difference? change the coils around and see if the bad spark follows the change??
Ebay usually has packs/coils.

http://standardmagneto.com/Parts.html these people sell new and real good prices.
I did a compression test on both cylinders and they were both at 95psi. I checked the output of both coils and one was not producing much so I ordered a replacement for it. Thanks for all of the advice. I appreciate all of you.
 

jerryjerry05

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May 7, 2008
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Before you buy!!! try swapping the coils around and see if the weak spark changes when you swap them.
In all my years, I've only seen 1-2 bad coils
 

Sdistad

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Joined
Jun 29, 2022
Messages
7
Before you buy!!! try swapping the coils around and see if the weak spark changes when you swap them.
In all my years, I've only seen 1-2 bad coils
Can swapping coils be as easy as switching the top leads off the top of the coils at the connection that looks like a in-line fuse?
 

jerryjerry05

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May 7, 2008
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Yes, just unscrew the black connectors and switch them around.
Change the plug wires too.
 

Sdistad

Cadet
Joined
Jun 29, 2022
Messages
7
Can swapping coils be as easy as switching the top leads off the top of the coils at the connection that looks like a in-line fuse?
Yes, just unscrew the black connectors and switch them around.
Change the plug wires too.
I switched the coils and the problem followed so I replaced the bad coil and it ran great all day. Thanks again for all the help.
 

jerryjerry05

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May 7, 2008
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Amazin how the littlest things help!!
You were lucky it was just a cheap coil, the stator can be 180$ or more.
 

jimmbo

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May 24, 2004
Messages
13,446
I switched the coils and the problem followed so I replaced the bad coil and it ran great all day. Thanks again for all the help.
See, a bit of troubleshooting isn't all that difficult. Glad to see you found the culprit
 
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