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View Full Version : Holley Carb Help...Ugh!!!


thwack
07-07-2008, 03:53 PM
I posted a thread earlier asking about a tranny problem with a 79 Stars and Stripes. The only comment I had back suggested a carb problem. That's where my original thoughts were, but I'm just clueless. I've spent the last 4 weekends working on the boat, and man is that frustrating. I put a new Holley 4160 on the boat two weeks ago, but there is still no power. The boat won't come out of the hole and really boggs in a turn. The carb seems to be working well and the mix seems right. Once the boat planes, it runs well, but try to turn around or take off from a sit still and it feels like driving a 21' bass boat. Does anyone have any clue what would cause this lack of power in the turns and out of the hole?

ski_king
07-07-2008, 04:11 PM
what prop is on it?
does it have the 1:1 transmission or the 1.52:1 (powerslot) transmission.

If it has the 1:1, the prop should be 13 x 13
If it has the 1.52:1 it should be 14 x 18

thwack
07-07-2008, 04:21 PM
I'm not 100% sure so I'll have to check this afternoon when I get in. The boat ran like a champ last summer with the old carb, but the power valve went out so I ordered a new one. The boat hasn't ran the same since I put the new carb on.

Dan K
07-07-2008, 04:21 PM
what prop is on it?
does it have the 1:1 transmission or the 1.52:1 (powerslot) transmission.

If it has the 1:1, the prop should be 13 x 13
If it has the 1.52:1 it should be 14 x 18

There is a shaft size difference between the two props so having the wrong one is unlikely. The 1:1 is a 1" shaft and the 1:1.52 is a 1 1/8" shaft.
You still may have the wrong pitched prop and should start with the ones Ski King recommended above.

You may also look to make sure your fuel float level is set correctly. this may be starving your boat in turns and takeoff.

ski_king
07-07-2008, 04:24 PM
I was thinking the previous owner may have over proped it for more speed and lost its power.

But if it ran ok last year with same prop, this is not the problem.

Also, it is unlikley it is a powerslot being a 78. I think late 78 was when they came out with that option.

thwack
07-07-2008, 07:59 PM
Thanks for the advise. I called Holley and asked one of their techs his opinion on the issue. After talking with him, I took the boat out on the lake and looked for the items he told me about. For some reason, the secondary is not opening up so I'm running a 2BBL instead of a 4BBL. The carb is new so I don't know what's causing the problem (I know new doesn't mean good always).

herevard
07-08-2008, 07:00 AM
I had the same problem recently. Cloged advance mechanism was a cause. Also check for vacuum leaks between carburator and spacer, spacer and manifold. Vacuum must be about 16 inches at idle. Best regards from Lithuania.

denverd1
07-08-2008, 10:24 AM
Is there an RPM range that it likes? If it runs ok up to 3000 RPMS or so, then timing advance could be suspect. I'm in the process of rebuilding my '86. One of the final projects, as suggested by JimN, was to inspect the advance weights and springs. Once I understood what was going on, i believe it created most of the problems I had before I tore it down.

It's safe to say that the carb and tranny are not the problem.

How high does it rev before losing power?

thwack
07-08-2008, 12:17 PM
It actually runs better at higher RPMs. The secondary never kicks in, but it does not lose power. The lack of power is on the low end. The secondary never kicks in so it has no power out of the hole or in the turns. Once I'm up to around 2k RPMs, the boat does fine.

thwack
07-08-2008, 12:35 PM
Alright, I spoke to the tech at Holley again this morning and he's telling me that it may be the squirter size on the carb. I'm somewhat "mechanical" but not a mechanic, so I don't really know. My understanding is that the vacuum secondary is only designed to kick in around 2000 - 2700 RPMs depending on the size of the spring. The hole shot is determined by the primary, which is controlled by the acclerator pump and squirters...right?

Storm861triple
07-08-2008, 07:28 PM
Alright, I spoke to the tech at Holley again this morning and he's telling me that it may be the squirter size on the carb. I'm somewhat "mechanical" but not a mechanic, so I don't really know. My understanding is that the vacuum secondary is only designed to kick in around 2000 - 2700 RPMs depending on the size of the spring. The hole shot is determined by the primary, which is controlled by the accelerator pump and squirter's...right?The "shot" is determined by the size of the orifice in the discharge nozzles (Squirter's) and the pump stroke, which is tunable.

If you had an accelerator pump issue, the symptom would be stumbling and possibly stalling, cause by and instantaneous over rich or too lean condition. The condition would be worse, the faster you move the throttle lever.

To me, your posts make it sound like the motor runs "fine" (no stumbling or stalling on throttle tip in), but simply lacks low RPM power.

If that assessment is TRUE, then neither the accelerator pump, the pump shot, nor the "squirters" are the issue. Is the above assessment correct?

-Tom

TCrate
07-12-2008, 10:52 PM
I think you really need to look at your distributor. Get a timing light and run it up with the light on. If it is staying at the same timing running it up through the RPM's it is not advancing. If it is moving note the timing at that major RPM points. 100,1500,2000, etc. Good Luck.

Storm861triple
07-13-2008, 01:41 PM
I think the OP moved onto another thread, since he never answered my question.

FiremansMC
07-13-2008, 04:50 PM
This sounds kind of like the problem I was having a couple years ago. We got a new carb. and headed to the lake. We put the new carb on and still have the troubles. So then we put the old one back on and tried it with that. Still had trouble. Then we got to messing with the timing. When we checked it with a timing light it was right on. So we took off down the lake and started messing with the setting. We just kept turning it back and forth until the boat ran good. Ended up fixing our problem when we got it to that sweet spot. Hope this helps.

Storm861triple
07-13-2008, 07:28 PM
I agree. I've made that exact suggestion on this board before, and I suggest it (over using timing marks) for a variety of legitimate reasons. However, I generally quickly get shot down. b/c it's not "by the book".

But yes, I agree that this method not only works, but when done correctly and depending on the conditions, can produce better results then even the sacred "book".

thwack
07-13-2008, 09:57 PM
Sorry to not be responding to this thread. I placed another thread called "My Last 'Help Me' Thread" that encompasses all of the problems. Either way, I've posted my findings on that thread and the problem is the firing, hopefully the dist cap. I'll find out Tuesday when my new dist cap comes in.