Quick fuel carb install questions

When I put my 4 bbl on I got the same degree wedge that HM used on their 2 bbl. You can see here how it looks. When I transfered this carb to my PCM with no wedge I had to do more adjusting than I thought .

I seem to remember he tried float adjustments, it works for him with reduced pressure and like I mentioned, others do it too so why worry about it.

Like he said, it works just fine for him

cbr1000dude wrote: I guess I'm the "bandaid" guy that lowered his FP to 3 psi to make my Holley quit dripping after shut off, and it still works fine thank you.

You did come to mind, but don't feel like the Lone Ranger

Thanks Scootdog!

Keno, I finall got the holley running late yesterday while I was waiting for my M-600 to arrive. I haven't given up. My brain won't let me no matter how much I want to.

I ended up checking the fuel filter and the fuel pump. I measured discharge pressure of 7psi so I ruled it out. Disassembled the carb and cleaned it all again. Pulled the PV and tested it since I had the backfire. I removed the old needle/seat assembly and installed the new one that came in the kit. The new one was a little different dimensionally. I mic'd the needle and the new one was .014" shorter than the old one. The new seat was .019" shorter than the old one. I adjusted the float a few times to compensate for the difference in the needle/seat assembly and finally got it where it was operating much better (not dripping during idle). It still has a little drip once I shut the boat off but its pretty minimal. The boat ran well with noticeably better throttle response throughout the RPM range up to about 4k. It would restart with a single turn of the key which was very uncommon before. No pumping the throttle and multiple start attempts. Not anything like it was before.

At this point, I have had so many issues I just don't really trust the boat. It'll run well for a few outings and then out of nowhere it'll have some issue. I figure the M-600 will at least make it much easier to adjust the floats if needed without taking the primary bowl all the way off.

When I bought the M-600, I also bought a new Ignitor II EI module and the corresponding 0.6ohm/45kV coil to replace the current setup (Ignitor I / 0.8ohm/40kV coil) but I realized that I ordered an oil filled coil and not an epoxy one so I sent it back today.

My plan is to run the boat as-is for the remainder of the season and rebuild the holley completely over the winter when I have some spare time. I will also install the M-600 and probably the new Ignitor II module and epoxy filled coil at that time. Then I will have a spare carb, EI module and coil standing by. Usually for me, if I'm prepared for everything, nothing happens. Fingers crossed!

fuel line

since you had other posts about your Holley having the drips, I see you gave up on the Holley,

Did you do the things people suggested like making sure the tank and everything upstream of the pump is clean so your new carburetor doesn't come up with the same problem?

You'll get opinions both ways on the fuel line, if you go flexible you should be using USCG approved stuff It'll have USCG A1-15 for a rating and it's stamped on the hose.

It's more resistant to fire than the typical auto hose or even the Aeroquip type braided hose.

You'll get opinions on regulator and gauge setups too.

Myself I'd use a gauge as a temporary thing to troubleshoot and you shouldn't need a regulator with a pump that puts out around 5 to 7 psi, but some people seem to lower their pressure to 3 psi or so as their cure to things like the "drips". Some other people might call that a band aid fix.

what Ken sez +1

gun-driver wrote: https://www.youtube.com/watch?v=mE_xTUXQJQ8

Informative video , worth watching if you have questions.   You are going to like your QFT carb.   BTW Holley owns them now.

https://www.youtube.com/watch?v=mE_xTUXQJQ8

TRBenj wrote: You shouldn't need a raised flange arrester to clear the adjustable floats. I have used a few different non-raised 8" diam arresters on my qf750.

Tim:

I tried to use the standard flame arrestor, but it would not sit flush on the carb body -- due to the float adjust hardware. I probably could have used several gaskets in a stacked configuration to get over the obstruction. Instead, I went with a raised flange arrestor.

JQ

Tim, the 600 has shorter bowls than your big dual feed. The stock flame arrestor swill generally run into the adjustable float screws and won't seat on the carb flange. You could make a spacer or seek a different arrestor.

It could also be that the rear bowl doesn't have a metering block I can't remember exactly.

When I get back to the house, I'll go look at my QF M-600 and see what I did with the flame arrestor bolt. If memory serves, I found a bolt in my bin that was the right diameter and thread count. Then I bought a new S/S bolt that was the correct length from the local big-box hardware store.

One note...I had to change-out my original flame arrestor as the QF carb has adjustable floats. The adjusting hardware did not allow my original flame arrestor to sit flat on the carb. I needed a raised flange type of arrestor. I decided to go for a little chrome bling and bought a K&N marine flame arrestor/air filter unit.

JQ

Not sure how it can be the same as the holley, when the the center bolt I took off my holley is too large for the QF M600....it/the holley center bolt, is noticeably larger than the boss (threaded receiving hole) on the M600...this size difference can be seen with the naked eye.

The connecting bolt that came off my Holley had a nice black hard- plastic screw down knob at the top, a little less than an inch in diameter. Is this the one that should fit the QF M600?

If so, the only thing I can think is.....if the "boss" isn't plastic, is it metal underneath some plastic-like protective coating, and would the original Holley bolt actually fit the M600 boss if I force it and grind through the black coating on the "boss"?

Otherwise, it needs a smaller diameter bolt of some thread type that I can't find. I tried an M6 (or M8?) diameter machine screw, which will make about 1 & 1/2 turns before tightening up because the thread pattern is wrong (too fine).

My only critique so far is that the QF carb doesn't come with its own (top hat) air filter unit, the Holley filter fits fine, but the center connector bolt is a different size that the Holley air filter connector bolt (the Holly bolt with the nice round black screw knob is too large in diameter for the QF carb). I tried a smaller, 3-in diameter metric machine screw, but the thread is wrong (the mach screw thread too fine I think). This center bolt screws down into what appears to be a plastic (black) threaded receiver hole on the QF carb.

I can't tell if the QF receiver hole is a black plastic coating over a metal receiver hole, or really jsut plastic...either way, I don't want to strip it with the wrong size/thread bolt.

I have a question in to the QF guys, but thought I'd ask here as well.....anyone figured out the specs on the correct center bolt for bolting down the top hot air filter element to the top of the QF M600?