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Old 05-30-2008, 08:46 AM   #1
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Unhappy Problems after Pinch

Hello, I need some advice from you engine guru guys I had my vspec piston\sleeve pinchrd for me.

I had this done probably 1 month ago or so. I initially put it all together and couldn't get it to run so I have been using the RTR mach 427 engine. I'd like a real race engine in my buggy so I am trying to get that vspec running again.

Before I sent it in the problem was wanting to stall all the time, even with a good tune. I'm hoping you have seen my problem before and can help me.

Biggest problem seems to be it just does not want to suck up fuel. I've replaced all gaskets (between pipe and header too), set needles to stock settings, sealed the carb and backplate, changed the plug, added\removed shims, etc. Even when I hold my finger over the exhaust is just won't pick up fuel. I think it has sucked some up some fuel here and there, but nothing to make it start. It will attempt to fire if I dump a little fuel on top of the piston.

Dropping in the 427 and changing nothing else the 427 runs fine. And has no problems picking up fuel.

I have totally taken apart the carb to ensure nothing is clogged or blocked. I've checked that the piston and sleeve are in fact in the correct positions. The sleeve notch is lined up with the notch in the case and the "tall" side of the piston is facing the exhaust hole.

What am I missing?

Last edited by LosiSuperTruck; 06-01-2008 at 06:41 AM.
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Old 05-30-2008, 09:18 AM   #2
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Sounds like you checked everything. Open the HSN and the LSN (at least 1/4 turn each) and try again. See if this helps the fuel flow. Open the flood gates, and see if fuel starts to flow. Once it does, then you can tune from there.

Also, disconnect the fuel line from the carb, put your finger over the exhaust, and hit the starter box. See if fuel flows without being connected to the engine.

There is not much to these little engines. Fuel should be flowing if the needles are set correctly.
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Old 05-30-2008, 10:04 AM   #3
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There may be an air leak somewhere in your engine. Go do a search on how to fix this problem. Have you tried, takin out the glow plug, keep the throttle body open (with air filter off) and blow fuel from your tank into the engine from the pressure tube connected to your exhaust pipe? see if fuel is going through first. then test for air leak.
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Old 05-30-2008, 04:42 PM   #4
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Could be something blocking a fuel pickup somewhere. Try blowing into the return line from the pipe and see if the fuel flows if not you have blockage or an air leak.
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Old 05-30-2008, 05:30 PM   #5
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Got it running. Turns out that when setting the needles to stock settings the mid range got screwed all the way in. I only noticed this while I had the carb in my hand during the rebuild. I would screw the low end needle all the way in, but when I started to back it out I felt the mid range moving as well. So as I backed the low speed out it would lean out the mid range.

Thanks for all the help.
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Old 05-31-2008, 08:56 PM   #6
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Glad you got it figured out, I was just coming in to suggest checking that. I've seen the issue on several engines and since it is one of those things you do not directly do yourself it can be a tricky fix.
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