engine lag

Since we have had first snow up here in Minnesota, it's time to deal with off season maintenance. Have been trying to figure out an issue with engine, and wondering if anyone has had experience similar. Under race conditions I am entering a roughly 65 mph corner and coming back on to power and hitting something that is similar to a turbo lag. Hit full throttle and acceleration seems to go flat then picks up throttle suddenly. Tough part is it comes on suddenly and induce wheel spin. Have thoughts it could be mechanical advance in distributor or possibly float level in carb. Any suggestions would be appreciated.

I'd first check the accelerate pump diaphragm. Sounds as if you are not getting a squirt and going lean until the main metering system catches back up

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Originally Posted by jtaphorn

I'd first check the accelerate pump diaphragm. Sounds as if you are not getting a squirt and going lean until the main metering system catches back up

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Thanks. I will check into that as well.

I had that once on my HFF, fixed after changing the Grose jet. The seat was old and not sealing properly, which actually was flooding my engine briefly before it could clear out. Fixed before the Sunday race and ended up with the weekends fastest lap!

Not unusual if the level is too high for a variety of reasons - not always a lean out thing
Phil

And sometimes you just have to learn to squeeze the throttle instead of asking for everything all at once (usually a sign you have overslowed). If you carry more mid-corner speed, you will find that you will have to squeeze the throttle open.

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Originally Posted by David Ferguson

And sometimes you just have to learn to squeeze the throttle instead of asking for everything all at once (usually a sign you have overslowed). If you carry more mid-corner speed, you will find that you will have to squeeze the throttle open.

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On the standard formula mazda we clean the carb every three races the Rotary Motor runs off the idle circuit when coming off the corner. If it is not right and you mash on the gas it will have a huge lag. I have seen Moses set the carb using the EGT and then adjusting the screws to get the lag out of the motor. You should call Moses Smith and have him go through the adjustments with you

Dwayne Anderson

Appreciate the suggestions. The lag is a recent thing, and I am thinking it might be the cleaning that was suggested. Thinking back, I changed the car over to eliminate the oil metering system and added oil to the fuel. It might be creating a little more gummy condition as it sits between races. Will also give Moses a call and see if he has any further suggestions.

Before you are entering the corner, is there a long strait where you could have drained to bowl? Or is there a long corner before where your fuel could have sloshed to one side of the tank and momentarily drained the pickup line?

If it's a sudden-onset thing check the float level and see if any trash has accumulated in mesh filter in the fuel inlet. As others suggested, check the accelerator pump assembly and see if anything is gummed up or broken there.