Perfect example. The diaphragm is not leaking, but the housing is. Shoulda been more specific on my part. Working for now, but just so you know next year when you change the diaphragm, you got a warped cover or something that should be stoned out, just sayin.

I'm still thinking this poor guys secondaries are not even thinking about coming to the party.............yeah, a 4150 Mechanical, and the butterflies are opening, but no fuel to support the secondaries? Ceramic filter in the bowl clogged? metering block clogged up? could be many things, but I think that carb needs to come apart.

Ray



Ray

Just to say this out loud....No way in hell you know that from your desk....No way. Been a mechanic for going on 25 years and I call BS..

 

GT

Well we made it up to big bear this morning and decided to run the boat tomorrow and relax today. I am getting the woosh sound at wot from what I remember and if I'm having lean issues they should be amplified up here so it might be a non tuning weekend I'll let you guys know tomorrow. And I'll definitely take some notes down, he'll I should be able to take video with this damn smart phone


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Ok guys now i have no idea. Just got off the water and ran like shit as usual at 3500 wot when I pulled it out I wanted to get the water out so I tapped it a few times and it hit 5200. What the hell? Haha so maybe it's a pump issue or some crap escaped from the fuel lines. While out on the water it did shudder a bit on take off then smooth out. Any ideas?


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Ok guys now i have no idea. Just got off the water and ran like shit as usual at 3500 wot when I pulled it out I wanted to get the water out so I tapped it a few times and it hit 5200. What the hell? Haha so maybe it's a pump issue or some crap escaped from the fuel lines. While out on the water it did shudder a bit on take off then smooth out. Any ideas?


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Free spin is a whole lot different than pumping a ton of water...Out of the water the engine does little/no work.


Testing the secondaries is quite simple, first, remove the flame arrestor/scoop/air cleaner and have someone floor the gas pedal with the engine off (make sure the choke is off if it has one), then look to see if the linkage will "allow" the secondaries to open (normally in the rear of the carburetor).

Once this has been confirmed, find the large dash pot on the side of the carb and push up on it with a finger, the secondaries should open quite easily. If not, bingo! If it does, there are four screws on the top of the dash pot, sometimes one will be hard to get to and the pot needs to be removed from the side of the carb with the two screws into the barrel of the carb body.

Inside the dash pot should be a yellow spring and a rubber diaphragm, chances are this diaphragm could be damaged, cracked or have a hole in it. It is replaceable and available separately as a repair kit....If the spring is any other color than yellow you may want to pick that up too....The yellow if memory serves is the lightest spring....And in my opinion the one you should be running...

Good hunting

GT

So can I rule out a timing issue?


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So can I rule out a timing issue?


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What proppy said...All needs to work together, get the tune dialed in so you know what it's "not"....

GT

My guess would be spark plug wires! They generally only arc against each other when under a load. Cheap and easy , one of the first things i would check if I was going to start ruling things out.

Thanks Hondo I'm about an hour away over in Montrose. So I pulled the dash pot apart and the yellow spring is in there, should I replace it with a bigger one? I read on Holley's website that it will bog at wot if the secondaries open too early...And thanks Marc I'll check up on the wires

Will do, yes. So my mechanic friend helped me out today. The timing was at about 30* btdc and the vacuum advance was always engaged even at idle so we pluged the hose to the distributor and retarded to 12* gonna see how she runs. Why the hell would my motor run half way decent at 30* btdc?


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Will do, yes. So my mechanic friend helped me out today. The timing was at about 30* btdc and the vacuum advance was always engaged even at idle so we pluged the hose to the distributor and retarded to 12* gonna see how she runs. Why the hell would my motor run half way decent at 30* btdc?


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What RPM was the timing at 30*? It realistically should be at approx.34-36* at above 2500 RPM, at idle it will probably work out to be about 20* (+/- 5*).

This is important because the vacuum advance allowed the timing to drop back down at WOT because of the lack of a vacuum signal (jet pumps use up all the torque a motor can muster). You do not need to plug the port on the distributor, it does not go anywhere, but the port on the carburetor will need blocked. Basically your timing advance was working backward for the most part. Possibly a huge part of your problem.

Keep in mind that timing marks should always be verified that they are actually at 0* TDC on cylinder 1, sometimes harmonic balancers can be off by quite a bit...
Good luck, now we're getting somewhere...

GT

Thanks GT, what I meant to say is we blocked off the carb. I'm not exactly sure what the timing was at idle because my numbers on that tooth lookin thing (what's it called?) only go to 16 below and 4 advance so 30 was kind of a guess. and that was at idle about 800 rpm. Do I have to pull the head off to see if the harmonic balancer is actually reading at tdc or is there another way?

take out plug #1 and crank it over with the starter. put your finger over the hole. TDC on the compression stroke will blow air out of the spark plug hole with your finger over it.  this way you know you're close.  i took a zip tie (something that isnt hard, or will damage anything if it breaks off in the motor) and poked it into the hole and watched while turning the motor over by hand when the piston was at its very top before going down again.  then i verified the balancer timing mark.  mine was a little off so i painted a line where it actually was.     

Thanks guys I'll give it a shot