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G'day All,
The tonner has a flat spot just off idle, which makes it a problem taking off, I have to rev it quite a bit and ride the clutch a bit and if I am cruising along in any given gear, and give it a bootful it hesitates and splutters a bit before accelerating, I had my dizzy regraphed a few weeks ago and the timing set by a specialist,but the flat spot is still there, what confuses me is that usually that means that its bogging down with a too rich mixture, but it has a standard carby with standard jets, and it has extractors and a sports system, which if anything should make it run ever so slightly leaner.This is driving me nuts so any advice on where to start looking would be very greatly appreciated, Thanks.
Russ
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That sounds more like its too lean rather than rich, and by the sounds of it its being caused by the accelerator pump. Look down the carby and open the throttle (with the engine off) and you should see a nice instant squirt of petrol. If its a 4 barrel c
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What Carby and Motor are you running?
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A couple of ways to go. The v flash way is a rolling road type dyno and exhaust sniffer, and get them to figure out what the mixture is doing as things are happening.
The moderately flash way is air/ fuel gauge and oxy sensors plumbed into the exhaust |
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I agree with Jabba. It seems to go flop in the transition phase. Thats between the idle and main circuit stages. Its a too lean issue. However, it maybe also be your accel pump being way too rich, and flooding the airflow/mix.
John
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Just had another thought, one which caught me out for ages. Check for manifold, carb gasket, PCV or rocker cover vacuum leaks. You spend all your time getting mixture set at idle with additional air getting in (i.e. way too rich for carb). Then when you |
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Keep the shiny side up, and the greasy side down. |
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G'day All,
Thanks for the replies guys, what I did was pull my carb apart and put a kit through it, and adjusted everything excactly as the manual says including acc. pump travel, tip height , float level, idle mixture, the whole kit and kaboodle, using
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Hi Russ.
Look down the carby, while you're operating the throttle linkage. If you you have a good sharp squirt of petrol from idle with no delay or slack in the linkage, your carby is OK.
The 4 other common problems leading to flat spots are.
Bas |
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Hi, My WB Panno has a similar flat spot problem. Its got 202 with a 4sp man and also will bog down and hesitate if I boot it while cruising. My dad bought it brand spankers from the show room in '82, and he reckons the flat spot has been there since Edited by user Monday, 6 June 2005 10:00:26 AM(UTC)
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my 253 blue motor did the exact same thing.
it was a stuffed diaphram in the pre pump (accelerator pump)
when you open it up it didn't get the squirt of fuel it needed to compensate for the time it took for the vacuum to form under the carb, start sucki
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Hi Russ,
At no stage here have you told us (a) what motor, and (b) what carby. We still dont know.
I would assume a Strommy, as u want to try a Holley, but that means a new manifold !!! So what the answer ?
John
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quote:
Originally posted by trubluhq
Hi Russ,
At no stage here have you told us (a) what motor, and (b) what carby. We stil
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Hi Russ,
OK. Well the single throat strommie is pretty basic. Not much to em at all. Are u running bog standard jets for a 202 ? I recall that if the main screw is too lean ie too far in, the transiton phase is effected. This may be part of it. It also
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quote:
Originally posted by trubluhq
Hi Russ,
OK. Well the single throat strommie is pretty basic. Not much to em at all. AEdited by user Wednesday, 8 June 2005 9:01:48 AM(UTC)
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Russ,
At this point I would find a carb shop that knows carbs. Not just one that says they do. Someone that is over 35 and knows what a 202 is !!!
From my old sidedraft (Holley & Dellorto) manuals (that I no longer have) it was possible to drill ver
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