BAD-HABIT

Just an update...I put the new Fuel pump on and installed a liquid filled gauge inline near the carb inlet....I had a good freind come over to lend a hand. Well sadly I hate to say that we didn't make much progress. We did rule out a few things though....After the pump change I noticed no change in the bog/backfire on a hard quick throttle jab...He however noticed that the carb was DUMPING fuel into the carb...The backfire we assumed was coming from the TONS of excess fuel...Well we decided to re-set the float drop to 15/16" as listed in the book. It had been at (their tech dept decision) at 1-1/4. I went from the stock 98 jets in the primary to the smallest I had which was 92. I changed the springs and rods to the slowest/leanest ones I had from my trick kit. The plugs had been BLACK and carbon filled AT IDLE ON THE HOSE. Well now the plugs were just very rich but not totally black. So A little progress there. But I shoudn't have had to adjust the damn thing THAT LEAN! The bog seemed to totally disapear and the backfires were ALMOST gone. Matter-of-fact I went about 20 or so quick throttle jabs without any bog or backfire.....BUT after letting the damn thing idle for 30 min or so I started to get the backfire back a LITTLE more. I noticed the carb was leaking fuel into the secondaries. I couldn't really tell were but it looked like it had to be from the gasket that connects the upper and lower parts of the carb. The fuel was starting to puddle in the corners of the rear of the carb. Not much but it was there..I replaced that gasket and re-checked the needle and seats (back to stock),float levels and everything else I could see. But when it was back together NO CHANGE I got a reply back from edelbrock that said the carbs could only handle 5.5 lbs!!!! This was after my new pump was reading 6lbs....Well I am getting tired of all this bull so I bought a Holley 750 vac. sec. Model 4010. Bought it off a fellow board member here. Supposed to only have about 30 hours on it..I figure Doing this will hopefully make all the holley lovers happy since it means taking off the Edelbrock And rule out one more possible problem (whats left? ) Just wanted to update everyone on the status of my "problem child". I will post when I get the carb on....Any suggestions on starting points for jets or sec. springs? Here is the carb I bought thoughts on this also..Thanks again you guys are the only thing keeping me from murdering this kid

BH

BAD-HABIT

Well lets see. Where to begin Since my last post I have made some definite progress. Well I installed the new Holley 750 and right away got rid of the bog going from cruise to W.O.T. Matter of fact I have some serious prop ventilation at about 4000rpm's W.O.T.! Picked up over 1.5mph. Jetting was for a bigblock with 74 primary jets and 76 secondary. I actually got some color on the plugs. Not very much but a little. If upped the secondary's to 82 and the primarys to 78. Plugs look PERFECT!!!. The mid-range power Ive picked up is awesome. The cruise miss was still present but at a smaller rpm range (3600-4200). I had a moment and thought since I had tried everything else I wired the Drew Shotguns wide open and WHOLA.....the miss was GONE!
I spoke with Drew and he said that ANY miss would be magnified 25 times with the shotguns based on the way they work. He said the miss probally was so small that it took the Shotguns to make it noticeable. Anyways I set the Shotguns on the loosest setting and set the closed positon to where it was actually open about 1/4". Now everything sounds great...SOOOOO Let's see Ive got the "miss" figured out,Picked up lots more torque and power, got rid of my bog at cruise not to mention got my plugs/motor running with the correct A/F ratio. Only ONE problem remains. I still have the severe bog going from idle to w.o.t. I have checked the float levels, no change. Advanced base timing to 10,12 and 14 with VERY little effect. Going from stock 8degrees to 10 made a VERY slight difference. I bought the 50cc pump and installed the biggest cam for that pump. It made a small difference. Noticeable but still small. I'd say going to 10 degrees initial and the 50cc pump MAYBE took 1/2 of the bog away. I have no idea what to do next I have to ease in to the throttle to get the boat to accelerate of the line even if its just a slight acceleration. After about 2-3 seconds Im o.k. Now sometimes during this way of accelerating I get a stumble/surge/cough sometimes I just get a slight bog then its ok. Sometimes I get a smooth transition. Now if I slam the throttle then I get the SEVERE stumble. If the boat is not in gear I can get a VERY slight bog on a idle to W.O.T throttle stab. Everynow in then a backfire. I was wondering if my problem could be anything Im overlooking I have checked and double checked EVERYTHING I can or anyone else here has thought of. I have one last thing Im concerend MIGHT cause the problem..........THE ALPHA SHIFT INTERUPTER.......COULD this be giving me any of the symptoms Im having??????????? As always ALL HELP IS GREATLY APPRECIATED Any thoughts AT ALL are welcome. Thanks

Randy
"Bad-Habit"

mopower

Randy,
You changed to a 50 cc pump , right? But did you change the squirters? Holley makes different size nozzles fpr this, and you can put 5 gallon pumps on , but there is only so much that will go though the squirters.
Because with the stumble and backfires off idle , it certainly sounds lean.
Another thought is the check valve in the accel. pump. If that's leaking or missing it will severely effect the amount you shoot ( excuse my terminology ) And again this would be MOST noticable coming off idle.

Just a few more ideas. Cal (mopower)

BAD-HABIT

Yeah I changed the pump. The squirters no. Actually I don't think you can on the 4010. But from what Ive read the squirters only determine the volume of the shot. I mean the cam/pump determine how much is shot the shooters decide at what rate and volume the fuel from the pump is shot....At least thats what my Holley book says...

BH

mopower

OK , the 4010 may not have replacable nozzles...I'm not sure about those
This did help a friend of mine on his. He had , what sounds like the same thing as you , only not quite so bad. He could accelerate normally , for the most part. But if he really hit it , he would get a stumble and occasional backfire . His carb had the removable bowls and metering plates , 4560 I believe.

bodacius

did anyone check the pick up tube in the tank for a restriction? i had this problem before, it showed up on the pyros, and after some searching, i found a collection of debri in the 90 coming off the pick up.surging , lean condition, and loss of power prob solved.

cbix

better put a vacumn gauge on that puppy cause you are suckin air someplace!!!!!!!!!!!

BAD-HABIT

Pulling between 14-1/2 and 15-1/2 pounds. Guage moves around between these two......

BH

formulaF302

this may sound stupid....but check your bolt lengths. Being that you've changed from stock bolts to ARP and have changed manifolds your bolts may even be bottoming out....just a thought from a similar experience with World Products heads and stock GEN VI head bolts......

formulaF302

mighta found my problem....using square bore carb on spread bore manifold...maybe you have a similar situation. I did'nt know that there is a special adaptor made for using such an application...but for the price difference I just bought new intake manifolds made for my carbs. Maybe you're dealing with a similar situation? Good luck.. Glenn