Another carb question...

[planedick]

I know that the float height effects mixture, but I'm beginning to think it only effects the idle mix except when it's so low it runs out on the top end. After I got the cam timing set I was experiencing VERY lean conditions. Syncronizing and raising the float made the idle OK, but excelleration in the bottom end was misfiring and crapping on the top end and VERY lean. Lowered the clip on the needles and top end and midrange is OK, but now idle is WAY too rich. It appears that needle position effects idle mix too. I wonder if lowering the float will help lean out the idle mix?

[motoman]

I'd go back to your original clip setting and go up a step or two(one step=2.5) in the mains. You want a happy medium of mileage and performance. My 81 Venturer loved 115mains for response and performance gains, but mileage suffered and plugs had a 'dusting' of black, so running 110's which is stock for sea level(go figure at 5,000ft.), but float levels are lowered at 25mm. Don't know what year you have but it's all realative to cause and effect, same difference.

[HobbyMan]

I would do what he said. Set float height as per manual. Adjust mixture by the jets

[planedick]

Why????

I don't understand what could make it so far from stock set-up. Stock airbox & filter, stock pipes and mufflers??????? My question was, "Does float height effect only the idle mix, or does it effect both idle and high speed mixture?"

[mason79]

Re: Why????

Originally posted by planedick
I don't understand what could make it so far from stock set-up. Stock airbox & filter, stock pipes and mufflers??????? My question was, "Does float height effect only the idle mix, or does it effect both idle and high speed mixture?"

try this richard

http://www.factorypro.com/tech_tunin...m_engines.html

[mro]

Sounds like your trying to adjust the carbs to solve a problem that could be something else.

All cylinders firing??
(can do the sizzle test on headers to see if all firing near the same)
Have you checked to be sure there are no vacuum leaks?
Carb boots sealing good on head, rubber seals good on throttle shaft, diaphragms, vacuum lines and the two plugs good? Vents clear?

78E float height 24.7 to 26.7 mm (25mm works)

When I get to a point of frustration, generally start over with the basics. Could be something that was taken for granted as good is not.


mro
btw, read a post last year where a guy had lost a socket, which had wound up in the inlet for filter box. Kinda like having a full time choke on

[planedick]

Float height

I have an infrared heat gun so I can check the pipes at idle for heat eveness. I think it's better than the water splash. New spark plugs. One thing for sure, I have become an expert at getting those carbs off and on. Changing needle clip positions is really easy without taking the carbs off.

[planedick]

Thanks

A thank you to Mason, very good information. Looks like you have spent more time doing searches than I have. Interesting that page has no information about who or where they are. Sure wish I had a dyno here, putting the tank and seat and all the other stuff on just to do a quick test is time consuming.