Author Topic: pressure/vacuum test?  (Read 3229 times)

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Offline Toom038

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pressure/vacuum test?
« on: May 28, 2013, 09:08:58 AM »
Does anyone know what pressure and/or vacuum I should use to test a 500 motor? I have a '99 that I can't get jetted right. I want to eliminate all other issues before I go postal on this carb and put a new one on it. I'm at a 180 main, 52 pilot and stock needle at 4th clip from top and it still blubbers off the bottom. Floats are set at 16mm and I put a rebuild kit in the carb. Seems fat on the bottom and then hits hard at upper mid. I'm right at sea level, running 50/1 93 pump gas. Is there something else I could be missing? Thanks in advance.
« Last Edit: May 28, 2013, 09:28:59 AM by Toom038 »

Offline sandblaster

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Re: pressure/vacuum test?
« Reply #1 on: May 28, 2013, 11:44:23 AM »
Should hold 7lb positive and negative pressure overnight.
Thank Yodarad for the info :-)
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline joko

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Re: pressure/vacuum test?
« Reply #2 on: June 30, 2013, 11:09:43 AM »
 I tried a 2" expansion plug in the exhaust port to seal it. It was a little too small by about .080", so I wrapped electrical tape around the rubber OD and put it in. It still leaked, when I checked it with soapy water, I think the grooves in the exhaust port from the pipe contributed to the leaking, but couldn't get it to seal after many attempts. Anyone have a better plug solution?

Offline Gage

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« Last Edit: July 01, 2013, 03:48:53 PM by Gage »

Offline sandblaster

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Re: pressure/vacuum test?
« Reply #4 on: July 01, 2013, 04:12:29 PM »
I'm wondering... Since it only has to hold 7lb have you tried some black RTV?
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline Toom038

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Re: pressure/vacuum test?
« Reply #5 on: July 02, 2013, 01:41:13 PM »
I found a plug in the plumbing section at my local Ace hardware store. It worked fine. No leaks. Thanks for the info here. I got her running really well now thanks to the knowledge of you guys. It was the float height that was screwing things up. Checking it externally found the issue.