Gpu220 losing power at full throttle

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walkertime1995
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Gpu220 losing power at full throttle

Post by walkertime1995 » Tue Feb 11, 2020 6:26 pm

Both me and my dad have gpu220 with Holley 500 2 barrel.
Both doing the same thing. At WOT it starts to lose power after about 5-10 seconds. Have electronics fuel pump and pressure seems to be good. What can be cause the loss of power?

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kwanjangnihm
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Re: Gpu220 losing power at full throttle

Post by kwanjangnihm » Tue Feb 11, 2020 7:10 pm

walkertime1995 welcome to SA!

here is a great link with things to check on! hope this helps :thumbleft:

viewtopic.php?f=47&t=69917&hilit=holley+wot
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walkertime1995
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Re: Gpu220 losing power at full throttle

Post by walkertime1995 » Wed Feb 12, 2020 8:29 am

I appreciate it. I will check it out.

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John Fenner
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Re: Gpu220 losing power at full throttle

Post by John Fenner » Wed Feb 12, 2020 9:09 am

Remove the scintered bronze filter in the bowl inlet.
I never finish anyth,,,.

walkertime1995
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Re: Gpu220 losing power at full throttle

Post by walkertime1995 » Wed Feb 12, 2020 11:26 am

I don’t see any type of filter on mine. Where would it be located or do you have a picture of what I should be looking for

gpu rick
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Re: Gpu220 losing power at full throttle

Post by gpu rick » Wed Feb 12, 2020 4:38 pm

It could be many things. I would check your magneto check to see If you have carbon tracking in your terminal block your mag could be shorting out. This is a common thing in aircraft engines that lose power at higher rpm. Had a lot of people bring there gpu's in to fix and they think its the carb and its not.

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Slidin Gator
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Re: Gpu220 losing power at full throttle

Post by Slidin Gator » Wed Feb 12, 2020 8:15 pm

A clogged fuel inlet filter is the best match to the symptoms described. I run Quadrajets but it is the same symptom. A clogged inlet filter will restrict the flow, the bowl will stay full at idle and part throttle, but at full throttle it won't let enough fuel through to keep the bowl filled. So you get max performance for a few seconds, then WTF. 2 boats (same owner) showing the same symptoms makes for a stronger case that this is the issue. Just change them every year you will look at the filter and not see any trash, but swap it and all is good.

I agree with John that removing it is a good trouble shooting move, but I dis-agree with removing it and leaving it out because the next problem is a piece of rubber etc. in a jet where it is harder to diagnose. Go buy 3 (per boat) at the parts store, swap one, keep one for spare and plan to sell the 3rd for $30 in the woods.

The filter in question will be inside the fuel connection on the carb, break out the 12" crescent.

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John Fenner
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Re: Gpu220 losing power at full throttle

Post by John Fenner » Fri Feb 14, 2020 10:08 am

I like to run a purolator inline pre filter, the glass type that has the replacement element, vs the inlet filter in the bowl, you can see the trash buildup to know the water separator needs replacing.
I never finish anyth,,,.

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