It'll be awhile before i fire the boat up but where do i hook the vacum gauge up to when i do? I assume i need to do this in the water and its frozen still here in Iowa. Just rev it up in neutral, or does it need a load on it? Sorry for the dumb questions but i dont pretend to know enough about carbs. Im going to tey to get my builder to come with me this spring but hes pretty busy between his work, 2 kids sports, and trying to drag race on the side.

On the base plate of the carb there should or may be some vacuum ports. Usually on the front. Need to use the one that full vacuum and not ported. If there aren't any you will have to plumb a connection in somewhere on the intake.

It's an Eagle but pretty much a GM clone recommending a 750. I'm not saying that it's a good recommendation, but it's their recommendation.

On my QF850M the vacuum ports are plugged off (no nipples) except for the big one on the back for the pcv valve. What's the work around on this for testing vacuum?

Use the port on the baseplate that the hose for the PCV is on. Temporarily unplug the PCV hose and put your vacuum gauge on that carb bung. You want to read manifold vacuum just under the throttle plates.

So what is the carb of choice? Quick fuel? My last motor had a prosystems holley and you would have sworn it was fuel injected the way it ran/ideled. But i know it had been sent back and had some $ invested in it.

In the little searching ive done the quick fuel marine version is the all black one. Any opinnons on this carb?

In the application I am referencing the Quick Fuel 1050 was set up correct out of the box from what I have been told. They were run the boat with a wideband monitor.

Bumping this thread.


Ordered the 850. QF. Recieved over the weekend. Looks like a nice piece. Installed and about ready to go.

I run an older holley mechanical fuel pump. Where does the vent hose from the pump suppossed to go?

For the life of me i dont recall where it was hooked up to if anything before the engine build.

Some setups go to the flame arrestor, some right into tue carb if the carb has the appropriate fitting

There is a nipple on the tall merc flame arrestors.