I have a new quickfuel 850 carb. Its on my rebuilt 509.

Everything is good except when i shift into gear it idles to low. I have the idle at 800, but when in gear it drops to 400 ish and is hard to stay running. In order to get a decent idle in gear i have to turn the idle up to over 1000 in neutral.

I have set the floats so they are half way up tje sight glass. All 4 mixture screws are out 1 1/2 turns from full seated

i know enough to ne dangerous when it comes to carbs. Is there any more i can do?

Turn the mixture stews out a bit more. Maybe as much as 2 turns. You need more fuel when in gear with a load on it.

try lowering the floats so the fuel is just above the bottom of the sight glass,to much fuel in the bowl will make the idle rich with no load on the engine.

What are your timing specs ?

Thanks for the replies

i originally tried 2 turns out on all 4 corners then backed each in 1/2 a turn. Didnt seem to make a difference if anything its maybe a little better at 1 1/2

timing is set at 34 all in. I didnt really mess with initial just let fall where it did but i believe its around 12 at idle.

The boat does seem to be running on the rich side. I noticed black soot on the transom the last few times out but my floats were still high so i blamed it on that and the fuel is from june 1 (87 non ethanol) due to the motor issues and being outta comission. Motor came out after i filled the tank. Lol. Teying to work it back down.

If you can tune your distributor to get more timing at idle it will help clean up a nasty rich lame idle associated with bigger cams. Try to get idle timing up around 20-24*. If you have an MSD distributor you change the stop bushing to achieve this.

See if Holly offers a marine carb in your CFM range. In our experience with Holley Marine Dominators, they solved 15+ years of jacking around trying to get the automotive Dominators carbs to idle in gear.

I once had the same problem and used a v-6 electronic box instead of my v-8 and it solved the same problem!

as said, look at timing at idle in gear, see if its backing off, either running full locked, if starting not a issue, or limited advance so you can run more base helps a lot

Thanks. Im gonna send the distributor back to msd over the winter to get rebuilt so ill look at locking it oit when i get it back

for now ill make it work till winter.