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Carter YH adjustments and setup

daderaide

New member
I had the carbs on my Interceptor 215hp 312 rebuilt by Wolf Enterprises ( YH guru) but I can't get the engine to run for more than a second or two. It starts up pretty consistently, but after a while, I have to refill the float bowls with gas to get it to start again. I went through some headache with the fuel pump where the previous owner rebuilt it and put the gaskets in backwards so the outlet port inside the pump was blocked. I fixed that and the pump seems to be working fine. It definitely pumps once the engine starts up, but lots of cranking does not fill the carbs with fuel. I have pulled the fuel line from the pump, filled the bowls and started the engine, and the pump does put out fuel once the engine is started, but not when cranking. Is that normal? This is a reverse rotation engine and I can't find the correct replacement pump anywhere. Has anyone out there put an electric pump on one of these engines?

I have been reading forums and searching for answers for 3 days and have tried ever suggestion I can find on adjusting these carbs but nothing has made any real difference. The idle mixture screw doesn't seem to have any affect. The idle speed adjustment also doesn't do anything. It just sputters for a few seconds and dies.

I have randomly had it run for 15-20 seconds every now and then and I have been able to rev it up a little if I move the throttle plate REALLY slowly but it seems like a fluke when it happens and then it still eventually dies. Holding the choke shut seems to help sometimes, but not always. I was able to set the timing roughly during one of those fluke 20 seconds of running, but I can't get it to run long enough to come up to operating temp.

The entire fuel system is brand new on the boat. I replaced everything as part of the restoration. New fuel lines, cleaned and sealed the tank, new pickup tube, new filter/water separator and filter housing, new shut off valve. Everything is new. I'm so frustrated with this and it feels like a dead end to just keep fiddling with it blindly. Does anyone have any ideas or suggestions? I can't believe that I will have spent months and thousands of $$ restoring this boat only to be completely defeated by these crap carter carburetors.
 
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As a 35 year owner of a 312 Y block with dual Carter YH carbs, I feel I may be able to help. First, get a pressure gauge in the line between the pump and the carbs. It sounds like you may not be getting the pressure needed. It should be very close to 4 PSI even when cranking the engine. Last fall I rebuilt my fuel pump with a kit from Then and Now Automotive. DO NOT even think about an electric pump. Keep the pressure gauge in the line. You will want to monitor the pressure making sure the PSI doesn't exceed the 4. If it does, then fuel may overcome the floats and flood the engine. If it is high, then a pressure regulator may be needed.

You mentioned the carbs have been rebuilt by a "guru" but I'd be concerned that they, being a Corvair shop, they rebuilt the YH's to marine specs and used the correct parts per the list number on the carb tags. (it's the little triangular tag screwed down to the top of the float bowls). Personally, I'd rebuild them again but go to Mike's Carburetor Parts. He has the YH premium kits. I rebuilt mine i 2009. Very easy! He also has some GREAT tutorials on how to rebuild every aspect of the YH's as well as setting all the adjustments. Note float levels are also marine specific and should be 9/16" forward and 7/16" aft.

Pump kit: http://www.then-now-auto.com/fuel-pumps/

Carb kit: https://www.carburetor-parts.com/


What's the 312 in? Mine's in a 64 Dunphy X55.
 
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Did you ever get your carb issues fixed? Sounds like you are not getting fuel to the carbs, most likely a fuel pump issue or plugged line somewhere.
 
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