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New engine start up...

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VelodromeRacer

VelodromeRacer

Jedi Trainee
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Need some thoughts here...

We have attempted to start the new 1275. It is just flooding the carbs..then of course fouling the plugs. I have the 1.5 inch Su carbs..and we upped the fuel PSI to 3.5 psi..and the carbs both have the float bowl spacers but plastic newer flaots.....so...

Backed off the fuel psi to 2.5...removed the float bowl spacers...not using Gross jets...but did but another shim under the jets...seemed better but still more fuel than should be...

Thoughts?
 
What are you trusting to regulate the pressure? If it's one of those "dial" things you need to put it with the Grosse Jets and use a Holley regulator.

If it IS a Holley, are the overflow pipes on the bowls leaking?
 
Velo--

What is the level of the fuel at the bottom of the carb? BTW MGA Guru doesn't have much good to say about those spacers:

<span style="font-style: italic">"During the production period for MGA Twin Cams there was a problem with a lean running condition which would burn pistons. One unsuccessful attempt to fix the problem was to install thin spacers to raise the cover on the float chambers, effectively raising the float and the fuel level to make the carburetors run intentionally rich. As this did not solve the problem at hand, the special part was quickly abandoned and was never a part of any production MGA.

Apparently someone had seen documentation of this part, or had seen it installed somewhere, and the reaction was, "Hey, another racing part we can sell for ten times what it costs to make". The part in the picture was fabricated to fit the HS type carburetors, which not coincidentally happens to be the big runner on pre-1972 MGB cars. It seems to be lost that they did not make the part to fit the original intended application of the H type carburetor, so this part does not even have any historical significance."</span>
 
Never saw the need for the bowl spacers. Getting any fuel out of the overflow tubes on the float lids? How about timing, I know, I know trying to get it started, could be grossly retard, try turning the dizzy to the right, see it makes a difference. The float level is standard race car or not, with the flaot lid upside down, the leading edge of the float should be about 1/8"-3/16" for the lid. Sure sound like a stuck needle and seat. 3.5 psi was a bit much pressure, but not drastic, 2.5-3.0 should be fine. Sounds to me like if it's not a needle and seat the carbs are not venting, that will coase that, got hose on the float vent tubes, are they clear?
 
Thanks all...timing..stuck needle...you name it!
Here is the video of the car...took it last Sunday to a test n tune day...wow is all I can say...the 1380 motor makes it feel like a race car now!

Next week...off to the VSCDA opener at Gingerman!

Youtube quick video of car
 
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