Does prop slip increase or decrease with speed? Top speed less than expected.
10-29-2014, 09:55 AM
#31
I had a problem on one of my engines 2 summers ago. One day the port engine would only hit 4500rpm and that was it. No stumble bog or hesitation. Just 4500 and that was it. Normally they turn 5500 no problem. Boost was there. Went back to dock, found fuel pump fitting on inlet side of pump loose. Fixed that went back out and reved right back to 5500
What are you running for fuel pump?
What are you running for fuel pump?
Actually toying with going back to a mechanical pump due to better reliability - block has the mounting boss and camshaft has the lobe.
So you were sucking in air at the fitting? I'm going to look for stupid stuff like that, including a cracked fuel pickup.
10-29-2014, 11:12 AM
#32
Registered
Budman FWIW we put a 533ci in a friend's baja 250 sport this spring, hit a whopping 60 first time out. It was way lean, threw some fuel at it and hit 69mph gps pretty quick. Listen to Mild, the tune is everything.
10-29-2014, 02:06 PM
#35
I'm going to check fuel delivery, timing, etc., and probably try jetting it richer just to see what happens. However, here's what I'm having trouble wrapping my head around: If it is jetted lean now, I would expect that it would have been lean on the dyno too, in which case I would think the A/F numbers would have told us, and it would not have made the power it did. How is it suddenly jetted lean now that it is in the boat? Especially with what should be more restrictive wet exhaust with muffled tips. Not doubting any of the excellent suggestions and advice I have had per se, just trying to understand what's going on.
10-29-2014, 04:15 PM
#37
Platinum Member
Platinum Member
Three years ago I warmed up a couple of HP 500's. They were in the 550hp range running fully dressed and wet exhaust on the dyno. We could not jet the carb fat enough. Ended up with 1000cfm pro systems. My guess is you are way too lean.
10-29-2014, 06:00 PM
#39
Registered
iTrader: (1)
I'm going to check fuel delivery, timing, etc., and probably try jetting it richer just to see what happens. However, here's what I'm having trouble wrapping my head around: If it is jetted lean now, I would expect that it would have been lean on the dyno too, in which case I would think the A/F numbers would have told us, and it would not have made the power it did. How is it suddenly jetted lean now that it is in the boat? Especially with what should be more restrictive wet exhaust with muffled tips. Not doubting any of the excellent suggestions and advice I have had per se, just trying to understand what's going on.
10-29-2014, 06:25 PM
#40
Registered
iTrader: (3)
Running a Carter black electric pump. => http://www.summitracing.com/parts/cr...FYxDMgodRUMAxA
Actually toying with going back to a mechanical pump due to better reliability - block has the mounting boss and camshaft has the lobe.
So you were sucking in air at the fitting? I'm going to look for stupid stuff like that, including a cracked fuel pickup.
Actually toying with going back to a mechanical pump due to better reliability - block has the mounting boss and camshaft has the lobe.
So you were sucking in air at the fitting? I'm going to look for stupid stuff like that, including a cracked fuel pickup.
Personally, i think that pump setup you have sucks. 18psi pump 100gph pump i see? And you are running a regulator down to 7psi i assume?
I know nothing about those pumps, and cant find the info on what it reallt flows at 7psi. My gut tells me to toss it in the lake though lol
If i were in your shoes, i'd invest in a six valve mechanical pump from baker engineering , or teague sells them. Self regulated , 1/2 NPT ports, will support more than enough power, and simple as can be.
