Quick Fuel M600

Alright dudes, this crazy place allowed us a few minutes to finally get the carb set up on Mark's 91 footer BBC.

We know the 600 is 50 CFM shy of the stock big block Holley but here goes.

We sorted a vacuum leak and put an initial tune on the QF (basically idle and no timing adjustments). Stock out of the box with no changes.

Good prop back on the boat and Mark did a short WOT run that netted 50.2 mph verified by Perfect Pass precision star. No lean pop or weird operation so my suspicion is they jetted it a little fat based on the small block QF says it was set up for.

Mark said it's way more responsive than the Holley and it is an animal out of the hole as compared before.

I will foot it and drive it soon to give my thoughts on the carb. The only complaint Mark had was the secondaries were coming in at 42-44 when pulling a footer. Should be easily adjustable with the secondary screw that the QF features.

The fastest the boat ever did before with the Holley was 51.3 ish if memory serves me but that was down river. So the thing lost no performance on only a preliminary tune. Hopefully we can plug chop it here soon and see if it is rich or lean.

Seems like it will be a great option especially for the small block guys. Mark is open to switch ups as we can sell this carb to the Fish Tique buddy if need be.

Only issue I had was the front float ran out of adjustment before I got it to the middle of the sight glass. Might have to take some things apart and do some bending if possible.

Mark footed it and put it away and came back about 5 hours later and it key started and hopped right up to pre set idle rpm. I am thinking one of those might find its way onto the brown boat sometime in the near future.

I am optimistic I can really tune those secondaries the way they need to be with the infinite adjustment screw they feature.

Hopefully we can check out the mixture and play with the timing some more and make it a consistent 51.xx boat. It is actually fairly impressive how well you can get something to run with a carb that is too small.

My car runs that early 625 speed demon series carb and makes in the neighborhood of 390 hp. It shifts at 5800 rpms and pulls through the traps at 6000-6100. I gather that a 600 cfm carb is probably completely adequate for a peanut head big block spinning 4800 rpms. Dial in fuel mixture (if it needs to be dialed in) and get a final run in with timing adjustments and I think it will be a boss.

Only other little thing he said eariler is it seemed every once in a while to stumble for an instant from a dead idle in gear to a completely WOT punch. I am thinking the accelerator pump nozzles may be just slightly to small for the BBC versus the small block tune. Maybe step up cc sizes on the accelerator pump diaphram. I plan to do some more on water tinkering and maybe give QF a call on that if it continues to be an issue.

Flooded the piss out of it when it had the vacuum leak to so the plugs probably aren't in the best shape at the moment either. Could be too that the float not being completely full and the fuel sloshes to the front of the front blow (instead of the rear like on a Direct Drive).

I have often thought turning the carb around on the big block V drive boats might be a better idea as it sits almost level anyways.

They look to be 30CC just like the Holley. It's very minimal so I think a cam or nozzle change would probably dial it right in.

I will double check the slop but I am pretty particular about that and the secondary closing rod when I play with carbs.