Cord

iTrader: (2)

I was hoping you could help me dial in my new carburator. I bought a 850 annular mighty marine demon from BG. If I recall correctly, it had 8x primary jets and 92 secondary jets. The secondary pv is plugged. 31 squirters? The carb idles very nicely. I actually have 2" more vacuum at idle than I did with my old holley. The problem is with the transition circuit. I'm still using the progressive linkage, but I have a 1:1 link on hand if you want me to use it. I thought that maybe I should have a powervalve on the secondary side with a 1:1 linkage. When the boat starts planing off, it will hesitate and then bog down. Working the throttle hard seemed to help, but things were so far off that it was hard to tell. The engine will back fire through the carb violently. Once strong enough to stall the engine. Thinking the engine was lean at the transition, we tried to rotate the cams (pink) to the number 2 position in the lower hole, instead of the number 1 postion in the upper hole as the carb came. This really didn't do much, but we were able to get on plane. We ran for a while and checked the plugs. The plugs where very clean and stark white. My dealer said the motor was way too lean and to go up 6(!) jets. Obviously this was way too much. It was the end of the day, and we finally gave up and put the boat back on the trailer. I need to reset my transfer slots, idle screws and idle ez. That'll get me back to the baseline. What I need help with is that transition circuit. Can you help me?

rbtnt

Cord, post some engine specs. I have the same carbs with the same problem when I am loaded with fuel and 4 or more people. My Demons are 930s on 540ci/650hp.



I'm testing some dominators this weekend.

CMS Racing

i would add a3 to 4 number in jet pri .and sec. change the squter to .33 and check the transfer and see if it is bushed down.you may have to drill the bushing out bigger? i don't think you need a power valve in the sec. food for thought

Cord

iTrader: (2)

Yep, 540's. Crane 741 cam. .610/.632, 236/244 @ .050. 1.7 rockers. The heads are fully ported winters castings. The engine made 580hp and 650is lb/ft. My old carb was a holley 850dp. The old one had 84 primary jets and a 6.5pv, 94 jets on the secondaries and no power valve. This carb has 83 primaries and a #6pv, the secondaries are 92's with no power valve. This one has #31 squirters. The cams are pink on the new carb. Both are installed in the #1, first hole. The old carb had a orange cam on the primaries installed in the #1, first hole. The secondaries had a brown cam installed in the #1, first hole. I'm thinking that the smaller secondary squirter is the biggest issue. I'm not sure how much the cams have to play with this difference though. Obviously the jets were pretty close, but the new carb must be running a bit leaner than my old one.

RumRunner

Cord,



Sorry for not getting back to you sooner, I'm out on Long Island right now. First try resetting the butterflies to show about .020" of the transfer slot. (It will look like a small square with the butterflies closed in their idle position) Turn the Idle-Eze in, and out 1-1/2 turns out. Set the idle mixture screws to about 1 turn out from seated. Reset the pump cams to the number 1 position. Set the float levels about 1/2 way in the window. If you're still having problems try raising the float levels up a little. If you're still having problems I'd increase the squirters to 37's or 40's. If you're still having the problems please let me know. You can reach me directly at [email protected]

Doug

Cord

iTrader: (2)

I'll be at loto the next time I get to tune this thing. I won't be able to contact you or run for parts when I'm working on it. I ordered 37 squirters last night. I also ordered a cam kit. I'm pretty sure that the smaller secondary squirter is most of my problem. But what if it isn't? What do I look at next? Also, at what point should I start fiddling with the cams?

dlbCheckmate

You should buy the Holley Accelorator Tuning kit. I think it is part number 36-184. It has two of each squirter and all the cams, along with diaphrams and miss parts. It's pricy at 110.00 but its a heck of a lot cheaper than paying 11.99 for each set of squirters. That way you have all the parts you could need. My o2.

Cord

iTrader: (2)

I saw that kit. I actually was able to buy the cams (which I apparently don't need), squirters, jets, etc. that I needed for less than the kit. I just didn't get all the little stuff the kit includes.

dlbCheckmate

I am up to a .50 squirter in the primary and .40 in the secondary with a green cam on the primary side, its better but still needs some improvement. Right now I'm fighting a milky oil problem. Gotta love boating !!

RumRunner

Cord,

Just give me a shout on my cell phone when you're out on the lake, and we'll get you fixed up.

Doug