220 loses power after 3 seconds

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riverhunter
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220 loses power after 3 seconds

Postby riverhunter » Thu Apr 17, 2014 9:50 am

I just got my engine back together and on my boat. ran it about 10 times on trailer. unloaded it in my buddy's pasture and decided to push it hard. throttle response was good but it will only stay at WOT for 3-5 seconds before losing power. blows a fireball out the exhaust, then revs right back up. im running holley 500, currently open headers, fresh gas. it will hold rpms between 500 and 2500 easy and only has problems between 2500 and 2850 (my max).
so do you think its a timing problem, lack of back pressure due to open headers or something else?
The VA said I'm crazy, so I bought an airboat.

220 GPU , 13ft unlimited glassworks?, nasty lookin 70/32 paddle

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Bruce
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Re: 220 loses power after 3 seconds

Postby Bruce » Thu Apr 17, 2014 9:56 am

Is your choke wired open reason i ask is under wot it could suck it shut always gotta check the simplest dumbest things first
12 foot Mamba "The Underdog"
Tired Gpu 520,Whirlwind Razor X

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Bruce
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Re: 220 loses power after 3 seconds

Postby Bruce » Thu Apr 17, 2014 9:58 am

Also are you running mechanical or electric fuel pump
12 foot Mamba "The Underdog"
Tired Gpu 520,Whirlwind Razor X

riverhunter
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Re: 220 loses power after 3 seconds

Postby riverhunter » Thu Apr 17, 2014 10:03 am

I'll check the choke tonight. I run a manual with an electric backup. the clear filter stays full the whole time.
The VA said I'm crazy, so I bought an airboat.

220 GPU , 13ft unlimited glassworks?, nasty lookin 70/32 paddle

GMAC 76
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Re: 220 loses power after 3 seconds

Postby GMAC 76 » Thu Apr 17, 2014 10:40 am

I remember some time back a fella had the same deal with the holley carb and the fireball and such and I believe he found out the power valve in the carb was either bad or the wrong one

loudmouse
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Re: 220 loses power after 3 seconds

Postby loudmouse » Thu Apr 17, 2014 1:39 pm

Sounds too rich to me.
14'X8' JW, Chevrolet 122CID LNF Turbo Engine, Ox box, 80" NGR 3 blade, 50" light bar, Two 9" light bars, some long ropes, extra gas(for my buddies)with pushpole and paddle. LOL

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riverrat1
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Re: 220 loses power after 3 seconds

Postby riverrat1 » Tue Apr 22, 2014 12:44 pm

If you didn't have someone set the carb up its not going to work call bobby Hoffman and and have him set it up .

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jinotown
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Re: 220 loses power after 3 seconds

Postby jinotown » Tue Apr 22, 2014 2:44 pm

I would check the intake tubes for leaks. That's a common problem on 220 GPU's. The standard main jets in that carb are close enough to keep it running good, just a bit lean. Do a compression check also. You may have something mechanical like a valve problem (cracked or loose seat).
13 1/2 Cottonmouth 520 Continental

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riverrat1
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Re: 220 loses power after 3 seconds

Postby riverrat1 » Sun May 04, 2014 8:37 am

If it was one out of the box take it of and find someone to do the mods to it . Bobby Hoffman is good at doing it one of the best .

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Bruce
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Re: 220 loses power after 3 seconds

Postby Bruce » Sun May 04, 2014 8:58 am

riverrat1 wrote:If it was one out of the box take it of and find someone to do the mods to it . Bobby Hoffman is good at doing it one of the best .


yep gotta do a bunch to em like put 76 jets in em and.... well thats it lol
12 foot Mamba "The Underdog"
Tired Gpu 520,Whirlwind Razor X

lotacarnage1
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Re: 220 loses power after 3 seconds

Postby lotacarnage1 » Sun May 04, 2014 10:23 am

sounds like float bowl is low and starving for fuel.does it run wot after it idles for a couble seconds?
smeller's the feller

hillbilly540
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Re: 220 loses power after 3 seconds

Postby hillbilly540 » Tue May 06, 2014 6:46 am

Sounds like a power valve problem. ..we had the same problem with our holley 500 and we put the 10.5 high flow power valve in it and we are running the 74 main jets and now it will hold the wot rpms and not fall off now....we also drilled out the pvcr holes to the next size up..The 2 little holes are under the power valve so once u unscrew the power valve u will see the 2 tiny little holes.
14'2" wide nose gilileo I0540 s/v , 74" sensenich NGQ

riverhunter
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Re: 220 loses power after 3 seconds

Postby riverhunter » Tue May 06, 2014 2:45 pm

Sorry I havnt updated everyone sooner. it was my mag. number 6 wasn't getting spark most of the time and a couple more where intermittent. GMAC 76 is taking care of my mag issues. Greg (gmac76) has been great to do business with. I highly recommend him.
The VA said I'm crazy, so I bought an airboat.

220 GPU , 13ft unlimited glassworks?, nasty lookin 70/32 paddle


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