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I agree with GT sounds to me like a lean pop at wot had the same thing happen to me check to see if you have a loose line at the carb could be sucking airHaven't checked that yet.. mybe that's the prob. Took it out last weekend and had no pop. Ran good. Maybe it fixed itself hahaha
A lean pop is what I was thinking...Rite on I'll have to check that. Thanks gt
Fuel pressure should NEVER drop below 5# on a Holley.
GT
The popping is likely not a flat cam, I would be more inclined to call it ignition "cross talk" or carburetion.What should the fuel pressure be at wot? I'm wondering if that could cause the pop
What compression ratio? If it's a low compression deal, you will want to stay smallish on the cam choice, if a cam is going, your best bang for the buck will be a tear down and possibly raising the CR and going throuhg the moving parts to ensure micro metal isn't having its way with you.
A quick oil analysis will clue you in to what's wearing out in the motor.
GT
First thing is to be sure you actually have a lobe going away, take an oil sample to see if there is any signs of metal. Then pull the spark plugs so you can perform a compression test to possibly pin point the problem cylinder, then pull off both valve covers and roll the engine over to check for excessive clearance between the rocker arms and valve stem tips. Then if you think you found the suspect lobe, install a dial indicator on a known good lobe, intake or exhaust, and take a lift reading at the rocker arm/valve and compare it to the suspect lobe. Sad news is, if you actually have a lobe/lifter that is failing; the metal contamination has already traveled throughout the entire engine's oiling system and impregnated into the cam, main & rod bearings, it’s time to completely dissemble the engine have everything properly cleaned and certain components replaced and prepare for a clean fresh assembly, that’s if someone wants to do it right, short cuts could result in another premature failure due to the residual contamination….good luckThe reason I think I have a lobe going flat is cuz it pops wide open. Total timing is around 32 and plugs look good. I should check compression again tho.... I once had a rocker arms stud break due to a collapsed lifter ( I think) but no damage was done.
PriceText or call the number and he can answer any questions. 👍
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Hey fellas! Was having issues with my starter making noises so i pulled it off and found one of the bolts was broken. Got new starter bolts and had the starter tested at AutoZone and they said it's fine. I put it back on and it's still making the noise. Does this sound like it might need to be shimmed?Whats your flexplate look like?
-Colt
I use 100 amp 1 wire marine alternator from the eBay, about 80 bucks free ship..Rite on I'll check that out thanks
your friendly local v-drive owner
What are the pros and cons of running a full synthetic oil compared to conventional? And with synthetic do I need to run a zinc additive for a non roller can?I'm not sure. But I run 20w50 Valvoline vr1. It has zinc in it.
Thanks!
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Only if it pops while under heavy acceleration to wide open throttle, the accelerator pump is "all in" by that point. If this is a standard square bore Holley vacuum secondary, the spring should be the lightest yellow one. One thing that happens sometimes is the fuel pump falls behind under heavy acceleration. One way to prove that is with a fuel pressure gauge at the fuel line. Pressure really can't be under 4PSI and never over 6PSI.Thanks for the advice gt I appreciate it. I'm leaning towards fuel delivery. I will put a pressure gauge inline and see what it says
Ignition timing could be funny too. I have seen sticky mechanical advance mechanisms cause what you describe. Easy enough to prove, run a timing light on the balancer and speed the engine up watching the timing advance, it should be quite smooth and increase and decrease with RPM....
Also depending on what carburetor, you could have a gummed up power valve. Or just the wrong power valve. I like the power valve to come in extremely late in the rpm range, you don't need the enrichment at 6.5", you need it at the upper registers so I like using a 4.5". This could change given your set up, but should be silly close... It also sounds like there could be some acc. pump issues, ensure the check ball isn't froze up or missing and make sure the nozzles are clear....
GT
First, there is a lot you can do to a vacuum secondary carburetor to make it work well...The only issue it has is a pop right before wot. At wide open it's smooth tho. Idle is smooth. Makes me think it runs lean at that point. That's why I'm thinking cam. Or maybe the spring in secondary?
Second, is it having an issue taking throttle from idle?
GT
Are you speaking of an accelerator pump cam?Well I didn't think of all that. Hahaha it's a 750 vac secondaries. I think the jet is 75 the build is basically stock. Ignition is hei
Depends on what carburetor, what size accelerator pump, engine build, nozzle size, ignition set up..... Everything.
This is like asking what shoe laces you like the best.... The information you get will be completely irrelevant.
What do you have cooking, let's go from there.
GT
So after spending several days, pulling my Panther Jet Drive in order to change out the steering cable and shift cable, I hooked up a new fuel line with a new Fuel Water Separator, hooked up my hose to the water system and went to crank the motor.Just make sure water is out of the cylinders. Put the plugs back in and fire it up. Turn your water on AFTER the boat starts
It was locked up? I turned off the water, pulled the plugs and cranked it over, to see a sprinkler system shooting water out of a few cylinders?
I had no issues with this before? Did I put to much water pressure? Stuck exhaust valve? Blown Head gasket? Please tell me it's something simple and it can be fixed with out pulling the engine apart?
Looking for an advice
Vacuum secondary? Gummed up with what?Not sure what it was. Piece of plastic or something.
GT
When you changed the distributor, did you use the same cap and rotor?Different cap n rotor. I took the vacuum secondary off and found the port gummed up. On the lake now and running good. Only thing is right before wot it pops but wide open runs perfect
How is the power wired to the distributor? Is there a relay? Or are you running straight from the ignition switch?
Voltage drop will do what you are saying, not enough spark to keep stuff lit.
Grab an inexpensive fog light relay and wire it to the distributor at the engine using the ignition wire from the switch to energize the relay and run a wire from the battery (or solenoid for the starter or other hot source) with a 12 gauge wire and the other side of the relay to the distributor....
GT
If you have an open in a plug wire or a cracked spark plug you would be having a miss all the time. If your only having this in the higher rpm range, it could be a possibility that your valve springs are getting weak or even have a broken one, check them all very closely, maybe it’s time to change them, springs only have so long of a life, heat and duty cycles will cause the coils to weaken.Never thought about springs. Makes a lot of sense to me. That's prob the issue
Try and take a video when it's poping ..It's a mechanical pump and bowls are full. Can that happen at high rpm?
and post it ... could be a fuel pump problem not pushing enough volume
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Msd box ?No box. Hei. Fires rite up. Idles smooth. Only when rpm is around 4500 it will pop
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