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Discussion Starter · #1 ·
Had a problem this weekend at the river. Boat runs fine above 1800rpms but after a cruise when I slow down below 1800rpms it loads up doesnt want to idle blows black smoke then would die and wont start until it sits for awhile(flooded). I pulled the sight plugs after it died fuel came out of front one, after I finally got it restarted I checked float levels seemed close but I adjusted it down a little anyway. ran the boat again when I slowed down did same thing would not idle, black smoke, etc. so i pulled sight plugs again front one had fuel coming out. Again after finally getting it restarted pulled sight plug and it was below hole.

Today i pulled that bowl off everything is clean inside needle &seat move freely.Carb is new only 3rd trip, ran perfect last two trips, fuel pressure is at 6.5psi carb is holley 850dp any thoughts on what it could be.
 

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Sit N' Spin
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Based on your post above, if I were to guess I'd say bad needle & seat maybe (needle not seating for some reason)? Does your fuel pressure hold constant as you increase RPM?
 

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Discussion Starter · #3 ·
Based on your post above, if I were to guess I'd say bad needle & seat maybe (needle not seating for some reason)? Does your fuel pressure hold constant as you increase RPM?

i did not check the fuel pressure while running did not think of it since it ran fine above 1800rpms. the needle & seat were replaced with the all metal ones when I jetted the carb.
 

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Sit N' Spin
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i did not check the fuel pressure while running did not think of it since it ran fine above 1800rpms. the needle & seat were replaced with the all metal ones when I jetted the carb.
Mechanical or electric fuel pump? Internal or external regulator?
 

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Sit N' Spin
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holley electric fuel pump (gen v block) with external regulator.
Another thing I'd check is the float itself...could be a slight leak in it not allowing it to float.
 

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Sit N' Spin
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how about the power valve?...i think a bad one could cause that condition!...not sure tho :)

FastRat
One thing a blown power valve WOULDN'T cause though is the bowls overfilling.
 

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Sit N' Spin
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If you have a friend with a carb would let you try to see if its carb related.
I believe he stated that only the primary bowl was overfilling itself...how can that NOT be carb related?
 

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E-7 Sheepdog (ret)
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Is that the black tip? if so then no they are all metal.
Ditch the plain steel needles and get the good ones with the viton tips.

According to my Holley Manual (disclaimer for the Jetaholic fans) the steel plain needles are intended for "alternate fuels", aka Alcohol and Nitromethane, not gasoline.

Metal parts, without a rubber/flexible non-metal seal surface will be nearly impossible to get to seal properly.

I would actually be not the least bit surprised if this setup is flooding at idle/near idle.
 

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Sit N' Spin
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Disclaimer #2 -

According to page #84, paragraph #3 of MY Holley manual (Super Tuning & Modifying Holley Carburetors by Dave Emanuel)...

"Holley offers both steel and Viton rubber fuel bowl inlet needles-and-seats. Viton units should be installed unless the fuel being used causes them to swell, in which case a steel needle-and-seat assembly should be substituted. Steel doesn't have the cushioning effect of Viton, so small pieces of dirt and scratches can cause leakage around the needle, resulting in a loss of fuel level control."
 

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Discussion Starter · #16 ·
Yeah I guess I can try the viton tipped ones I have them they came with the carb. But when I re-jetted it George at Clay smith said to ditch those and run the all metal ones. it is easy enough to try it though.
 

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Sit N' Spin
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Yeah I guess I can try the viton tipped ones I have them they came with the carb. But when I re-jetted it George at Clay smith said to ditch those and run the all metal ones. it is easy enough to try it though.
Based on the above information, I don't see why you would run anything but the Viton tipped ones on a carb set up for pump gas. As stated above, the metal ones are only used for alternate fuels that would normally cause the Viton rubber to swell...they're not a performance improvement dealio.
 
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