BigChris
Seaman Apprentice
- Joined
- Apr 25, 2016
- Messages
- 39
So here's my story, in 2011 I bought a very low hours immaculate condition Four Winns Horizon 220 with a cracked block and cracked exhaust manifolds. The previous owner, who recently relocated from Florida, failed to winterize the engine and well......she froze. I bought her knowing this, and the selling/buying price reflected this.
I am an engineer by trade, the son of a Snap-On tool man, I build race engines for dirt oval go karts as a side business (www.rperacing.com). I've repowered boats, cars, jet skis, snowmobiles before. I have a bridgeport in my 1000 square ft shop on my property. I'm pretty mechanical.
The original engine was 5.0L with the MEFI 4 system. So off to the junkyard I went, and grabbed a couple 5.7 liter small blocks. I bought the Eagle racing 383 kit from summit, and built a properly clearanced marine engine. .003" piston to cylinder wall with hypereutectic, .030" top ring gap, .035" second ring gap, 9.8:1 compression ratio. Valve train is designed to handle 6500 rpm, though it'll never see it.
I sent MEFI 4 computer off to Jim at Az Speed and Marine to have it reflashed. Disclosing the manifold was from a 305, and it had injectors from the original 305.
Bought the Rinda diagnostic tool to be able to set cam retard via the distributor, and verify ignition timing.
She starts amazing. She pulls out of the hole real strong. Top speed of 60mph, at 5200ish rpm (says the dash tach).
But here's my problem...........top speed run (WOT, flat water, perfect trim) she's tulipped the intake valve on #3 cylinder twice on me now.
I've verified fuel pressure 48psi, and replaced the injector on #3 cylinder after the first time. The second time was late last summer after a nice weekday high speed run at Raystown (there's nobody there on the week days).
So I've had it, since I lack the equipment to diagnose and reprogram the computer, and after several polite phone conversations with Jim S at AZ speed and Marine that went nowhere, I'll be converting this system to a carburated setup. I'll be removing the manifold, throttle body, fuel pump assembly, computer and crab style distributor. Those items will go for sale on ebay along with the Rinda tool.
I'll be replacing them with a mechanical fuel pump, Edelbrock intake manifold, Edlebrock 650 cfm carb, and a MSD HEI distributor. (carb and dist will of course be the marine type).
My plan is to document this effort here.
I am an engineer by trade, the son of a Snap-On tool man, I build race engines for dirt oval go karts as a side business (www.rperacing.com). I've repowered boats, cars, jet skis, snowmobiles before. I have a bridgeport in my 1000 square ft shop on my property. I'm pretty mechanical.
The original engine was 5.0L with the MEFI 4 system. So off to the junkyard I went, and grabbed a couple 5.7 liter small blocks. I bought the Eagle racing 383 kit from summit, and built a properly clearanced marine engine. .003" piston to cylinder wall with hypereutectic, .030" top ring gap, .035" second ring gap, 9.8:1 compression ratio. Valve train is designed to handle 6500 rpm, though it'll never see it.
I sent MEFI 4 computer off to Jim at Az Speed and Marine to have it reflashed. Disclosing the manifold was from a 305, and it had injectors from the original 305.
Bought the Rinda diagnostic tool to be able to set cam retard via the distributor, and verify ignition timing.
She starts amazing. She pulls out of the hole real strong. Top speed of 60mph, at 5200ish rpm (says the dash tach).
But here's my problem...........top speed run (WOT, flat water, perfect trim) she's tulipped the intake valve on #3 cylinder twice on me now.
I've verified fuel pressure 48psi, and replaced the injector on #3 cylinder after the first time. The second time was late last summer after a nice weekday high speed run at Raystown (there's nobody there on the week days).
So I've had it, since I lack the equipment to diagnose and reprogram the computer, and after several polite phone conversations with Jim S at AZ speed and Marine that went nowhere, I'll be converting this system to a carburated setup. I'll be removing the manifold, throttle body, fuel pump assembly, computer and crab style distributor. Those items will go for sale on ebay along with the Rinda tool.
I'll be replacing them with a mechanical fuel pump, Edelbrock intake manifold, Edlebrock 650 cfm carb, and a MSD HEI distributor. (carb and dist will of course be the marine type).
My plan is to document this effort here.