Hp 500
10-29-2011 | 11:19 AM
#1
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From: Saginaw, MI
Hp 500
I have a 27 Fever. I am runnung a HP 500 motor carb with about 100 hours on it. I am thinking about a whipple or a small blower setup. Does that motor need any modifications or can I just bolt and go. Of course I would keep the boost reasonable.
10-29-2011 | 11:30 AM
#2
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From: Saginaw, MI
Yeah I know I am just trying to decide if I should run it another season and get some more hours on it and then go through it and freshen it up and beef it up at the same time. But if I can bolt and go that would be even better.
10-29-2011 | 02:54 PM
#4
Ginger or Mary Ann?
Joined: Oct 2000
Posts: 11,030
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From: L
Ran a B&M 250 on my HP motor for a few yrs with no motor issue other than dialing in the carb. Only internal mod to the motor was head gaskets replaced to Felpros per recommendation of B&M by previous owner of my 27. Boost was 5#.
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10-29-2011 | 04:25 PM
#5
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From: Cincinnati, OH
I have a couple of friends running 27's with HP500's with 250 B&M's on them. One had a huge dominator (or demon, I don't remember anymore) single carb on his and always had idle issues - it would die often trying to dock the boat or get it on/off the trailer. The others had twin 750's and they never seemed to have those problems. I think the problem was that the air velocity was so low on that big carb, the jets had poor signal. Two of the stepped 27s' with the 250 B&M's and ~ 5 psi boost ran right at 80ish mph on gps. Biggest problem is/was a nasty chine walk with their stepped hulls around 75 mph 
. Dropping the tabs a little seemed to help, but scrubs some of the speed, too (nothing that cannot be overcome with even more hp, though
). One had stock circulator pump and no water pressure problems, another one had crossover and he always fought water pressure problems. I hink he ended up putting a pressure relief valve in the circuit. For props, they went to 28P B1's with 1.50:1 drive ratio's and those seemed to work well . Boat years ranged from 1991 nonstepped to 1999 stepped hull boats. One friend has just over 400 hrs on his, all with the blower on it, and the only engine issues he had was a valve spring changeout and valve job done at the same time. Hope this helps.
Bob
. Dropping the tabs a little seemed to help, but scrubs some of the speed, too (nothing that cannot be overcome with even more hp, though). One had stock circulator pump and no water pressure problems, another one had crossover and he always fought water pressure problems. I hink he ended up putting a pressure relief valve in the circuit. For props, they went to 28P B1's with 1.50:1 drive ratio's and those seemed to work well . Boat years ranged from 1991 nonstepped to 1999 stepped hull boats. One friend has just over 400 hrs on his, all with the blower on it, and the only engine issues he had was a valve spring changeout and valve job done at the same time. Hope this helps. Bob
Last edited by bob_t; 10-30-2011 at 04:05 PM.
10-29-2011 | 06:47 PM
#6
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From: San Diego
I have a couple of friends running 27's with HP500's with 250 B&M's on them. One had a huge dominator (or demon, I don't remember anymore) single carb on his and always had idle issues - it would die often trying to dock the boat or get it on/off the trailer. The others had twin 750's and they never seemed to have those problems. I thing the problem was that the air velocity was so low on that big carb, the jets had poor signal. Two of the stepped 27s' with the 250 B&M's and ~ 5 psi boost ran right at 80ish mph on gps. Biggest problem is/was a nasty chine walk with the stepped hulls around 75 mph . Dropping the tabs a little seems to help, but scrubs some of the speed, too (nothing that cannot be overcome with more hp, though). One had stock circulator pump and no water pressure problems, another one had crossover and he always fought water pressure problems. He ended up putting a pressure relief valve in the circuit. For props, they went to 28P B1's with 1.50:1 ratio's and those seemed to work well . Boat years ranged from 1991 nonstepped to 1999 stepped hull boats. One friend has just over 400 hrs on his, all with the blower on it, and the only engine issues he had was a valve spring changeout and valve job done at the same time. Hope this helps.
Bob
. Dropping the tabs a little seems to help, but scrubs some of the speed, too (nothing that cannot be overcome with more hp, though). One had stock circulator pump and no water pressure problems, another one had crossover and he always fought water pressure problems. He ended up putting a pressure relief valve in the circuit. For props, they went to 28P B1's with 1.50:1 ratio's and those seemed to work well . Boat years ranged from 1991 nonstepped to 1999 stepped hull boats. One friend has just over 400 hrs on his, all with the blower on it, and the only engine issues he had was a valve spring changeout and valve job done at the same time. Hope this helps. Bob
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10-29-2011 | 09:51 PM
#7
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From: West Hills, CA & Lake Havasu
Hi Chad,
Did you sell the 27'? I guess you are getting closer to that new 38' footer. Cool!
I like the P-38 in your avitar. A friend of mine just gave me one blade (polished) off the left prop, left engine of a P-38. It is mounted and on dislplay at my office in the show room. The prop on the left engine on a P-38 turns opposite of all other engines in all US WW-2 fighters. Pretty rare artifax.
take care,
Dave
Did you sell the 27'? I guess you are getting closer to that new 38' footer. Cool!
I like the P-38 in your avitar. A friend of mine just gave me one blade (polished) off the left prop, left engine of a P-38. It is mounted and on dislplay at my office in the show room. The prop on the left engine on a P-38 turns opposite of all other engines in all US WW-2 fighters. Pretty rare artifax.
take care,
Dave
