Losing a cylinder

J.Cribbs · 09-02-2013, 04:14 PM

I have a 23hp vanguard that starts and idles ok as soon as you hit the gas rear cylinder stops firing and then cleans up in the higher rpm's and runs fine until you idle back down and then repeat, from what I've read possible diode prob? How do I test this issue?

1989Marathon · 09-03-2013, 04:38 PM

Remove the diode wire harness, and check front-to-back ratio of the 2 diodes. To do this, check the resistance across a diode. Swap the meter leads and check the resistance again in the other direction. One reading must be at least 10 times the value of the other. Do the same for the other diode. You should find that it is much higher than that. 10 times is the minimum. If it is even close to 10x, replace the diode with a 1N2007 diode from radioshack.

J.Cribbs · 09-03-2013, 05:57 PM

Thanks I will try that when I get back home

1989Marathon · 09-03-2013, 06:06 PM

Please let us know what you find.

J.Cribbs · 09-04-2013, 11:04 AM

I had to leave town for a few weeks but as soon as I get home ill post my results

Pitbull Joe · 09-13-2013, 04:50 AM

Good luck on fixing it. I was thinking diode when we discussed it before, glad someone could confirm it.

J.Cribbs · 09-22-2013, 05:20 PM

What a nightmare I ordered a new diode harness and a new coil, I decided to change the coil as well since my fan exploded and cut the coil wire in half, I soldered it back together and figured maybe that could have been part of the problem. After I changed the parts and took it for a test run the same problem occurred so I went back to thinking it was flooding and I had already thought this before and cleaned the carb same problem, rebuilt the carb same problem so after thinking long and hard about lighting a match to it I figured I would try one more thing so I went and bought a new fuel pump and BINGO Problem solved! I never figured of fuel pump failure that would pump too much gas!

Pitbull Joe · 09-22-2013, 08:26 PM

Wow. Glad you got it figured. To be you had to go thru some much headach tho.

simple man · 09-23-2013, 10:44 AM

Quote:

Originally Posted by J.Cribbs

What a nightmare I ordered a new diode harness and a new coil, I decided to change the coil as well since my fan exploded and cut the coil wire in half, I soldered it back together and figured maybe that could have been part of the problem. After I changed the parts and took it for a test run the same problem occurred so I went back to thinking it was flooding and I had already thought this before and cleaned the carb same problem, rebuilt the carb same problem so after thinking long and hard about lighting a match to it I figured I would try one more thing so I went and bought a new fuel pump and BINGO Problem solved! I never figured of fuel pump failure that would pump too much gas!

I would check your crankcase oil for fuel dilution. (smell the dipstick for gas) Sometimes when a fuel pump goes bad it can allow fuel to be drawn into the crankcase. If you have any doubt, just change the oil and filter!

J.Cribbs · 09-23-2013, 10:57 AM

Thanks simple man I'm Gona change it again a few months ago it did that and was leaking out of the crank seal

09-02-2013, 04:14 PM	#1
J.Cribbs Gone Wild Join Date: May 2011 Location: Live Oak, FL. Posts: 263	Losing a cylinder I have a 23hp vanguard that starts and idles ok as soon as you hit the gas rear cylinder stops firing and then cleans up in the higher rpm's and runs fine until you idle back down and then repeat, from what I've read possible diode prob? How do I test this issue?

09-03-2013, 04:38 PM	#2
1989Marathon Gone Wild Join Date: Oct 2010 Posts: 6,730	Re: Losing a cylinder Remove the diode wire harness, and check front-to-back ratio of the 2 diodes. To do this, check the resistance across a diode. Swap the meter leads and check the resistance again in the other direction. One reading must be at least 10 times the value of the other. Do the same for the other diode. You should find that it is much higher than that. 10 times is the minimum. If it is even close to 10x, replace the diode with a 1N2007 diode from radioshack.
1989Marathon Gone Wild Join Date: Oct 2010 Posts: 6,730

09-03-2013, 05:57 PM	#3
J.Cribbs Gone Wild Join Date: May 2011 Location: Live Oak, FL. Posts: 263	Re: Losing a cylinder Thanks I will try that when I get back home

09-03-2013, 06:06 PM	#4
1989Marathon Gone Wild Join Date: Oct 2010 Posts: 6,730	Re: Losing a cylinder Please let us know what you find.
1989Marathon Gone Wild Join Date: Oct 2010 Posts: 6,730

09-04-2013, 11:04 AM	#5
J.Cribbs Gone Wild Join Date: May 2011 Location: Live Oak, FL. Posts: 263	Re: Losing a cylinder I had to leave town for a few weeks but as soon as I get home ill post my results

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09-13-2013, 04:50 AM	#6
Pitbull Joe Gone Wild Join Date: Feb 2013 Location: Plant City, FL Posts: 2,212	Re: Losing a cylinder Good luck on fixing it. I was thinking diode when we discussed it before, glad someone could confirm it.

09-22-2013, 05:20 PM	#7
J.Cribbs Gone Wild Join Date: May 2011 Location: Live Oak, FL. Posts: 263	Re: Losing a cylinder What a nightmare I ordered a new diode harness and a new coil, I decided to change the coil as well since my fan exploded and cut the coil wire in half, I soldered it back together and figured maybe that could have been part of the problem. After I changed the parts and took it for a test run the same problem occurred so I went back to thinking it was flooding and I had already thought this before and cleaned the carb same problem, rebuilt the carb same problem so after thinking long and hard about lighting a match to it I figured I would try one more thing so I went and bought a new fuel pump and BINGO Problem solved! I never figured of fuel pump failure that would pump too much gas!

09-22-2013, 08:26 PM	#8
Pitbull Joe Gone Wild Join Date: Feb 2013 Location: Plant City, FL Posts: 2,212	Re: Losing a cylinder Wow. Glad you got it figured. To be you had to go thru some much headach tho.

09-23-2013, 10:57 AM	#10
J.Cribbs Gone Wild Join Date: May 2011 Location: Live Oak, FL. Posts: 263	Re: Losing a cylinder Thanks simple man I'm Gona change it again a few months ago it did that and was leaking out of the crank seal

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