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18 hp twin briggs compression

pointman's Avatar

Join Date: Jun 2008
Posts: 2

06-23-08, 10:27 AM   #1  
18 hp twin briggs compression

Hi guys,
I have an 18 hp twin B&S in a 6 wheeler that starts easy and runs really well. I bought it a few weeks ago and decided to check the compression on it. One cylinder shows great compression, and the plug burns white in it, however the other cylinder shows no compression nor will it blow my finger off the plug hole, the plug for that cylinder burns black pretty quick. I'm thinking a valve problem, but wanted anyone's input here that might help.
It does backfire thru the carb when it's shut off, which I also believe is a valve related problem, right?

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rogerflies's Avatar

Join Date: Jun 2008
Posts: 150

06-23-08, 12:39 PM   #2  
The 18HP Briggs horizontal twin I recently acquired had both intake valves stuck open. It had no compression, but it would backfire through the carb when cranked over. The engine had sat idle outside for at least a year before I got it.

I was able to unstick one valve by inserting a dowel through the sparkplug hole. I had to remove the cylinder head to free up the other one. It ran pretty well after that.


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