using menometers

Re: using menometers

by bill martin » 14 years ago

bill martin

10 757 0

James,

The manometer actually measures the manifold vacuum behind the carb. If your manometer attaches to one carb at a time, just take a reading from each carb at idle. The higher the reading, the lower the idle. If you want to slightly increase the idle speed, raise the brass throttle adjustment screw on top of the carb which is giving you the highest vacuum reading. IF you want to slightly lower the idle speed, lower the adjuster on top of the carb that is giving you lowest vacuum reading. The idea is to get both carbs to the same vacuum reading. You should back out the big idle adjustment screws a turn or so if you need to lower the idle speed. Once you get the carbs balanced you can run the idle adjustment screws back in until they just touch the bottom of the carb slide, then go a quarter turn more. With the carbs balanced and at the proper idle speed, the slides should be resting on the idle adjustment screws and not hanging on the throttle cable. You should be able to lift the cable housing on top of the carb up about 1mm or so before the slide begins to move up. This assures that the slides will always return to the same spot at full idle. One double check is to have someone watch the slides as you advance the throttle (engine off). Both slides should begin to move up at the same time. If they don't move together, you will have proper balance at idle, but not at cruise. Hope this helps.

Bill

Re: using menometers

by James OKane » 14 years ago

James OKane

17 39 0

Thanks Bill, I have this tool and thought that I could put it to good use. It is a digital manometer and I should get some exact measurments.

Re: using menometers

by Nick Axworthy » 14 years ago

Nick Axworthy

16 325 0

Jame here is a page out of an old Rotax manual that I think makes it all clear,

Just to clarifie....is the gauge you have the type that you can connect to both carbs at the same time,

Apologies about it being upside down but it is rotatable...the one I made I filled with white spirit as we call it in the UK....I didn't fancy the water idea in case it got sucked in.

Nick.

Carbballanceutube.pdf (You do not have access to download this file.)

Re: using menometers

by James OKane » 14 years ago

James OKane

17 39 0

I can use two pieces of tubing and alternate the test on each carb. This is not like the one that is reviewed on this site. This manometer is made to test the pressure both positive and negative pressure for gas valves. The best feature about this devise is the accuracy to the hundred decimal.

Re: using menometers

by Nick Axworthy » 14 years ago

Nick Axworthy

16 325 0

Sounds like it maybe a fiddly job with your device James....the one in the link can be made for buttons....

Nick.