Hp500 efi Questions
02-06-2014, 01:44 PM
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Hp500 efi Questions
Can anyone help me figure out my two cylinders have chucks missing near the intake side of the piston and shiny spots on all the others by the intake valve? I bought this boat with a "rebuilt" Hp500 EFI and I got 20 hrs out of it and it was smoking bad so I tore it down thinking the rings didn't seat, I was wrong! It looks to be caused by detonation but why??? I re- rebuilt the motor but Im just not sure what caused this the happen in the first place. Any info for a first timer would be great.
02-06-2014, 01:49 PM
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100% stock tune? what did the plugs look like, and what plugs were in it ?
Did you do the initial set up and timing when you rebuilt it ,,,,, stock rebuild??
Did you have the injectors checked?
What was the fuel pressure?
Did you do the initial set up and timing when you rebuilt it ,,,,, stock rebuild??
Did you have the injectors checked?
What was the fuel pressure?
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02-06-2014, 03:03 PM
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Plugs were ac and looked good. I didn't check anything before I rebuilt it but I timed it to specs this time and yes its a stock tune. Just wondering if I should be worried it will happen again and what caused it to burn up. I can't figure out how to upload a pic. Fuel pressure at valve was 38psi. Im putting in a new pump in the spring just in case. Inj were sent out and cleaned and flowed. bored .030 new pistons rings and bearings. All top end was reused.
Last edited by NeverIINauti; 02-06-2014 at 03:05 PM.
02-07-2014, 12:14 PM
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what number A/C 41, 43, 45?
Also,,,, how do the valve seats look in the heads
+1 to oxygenated fuel causing issues
Also,,,, how do the valve seats look in the heads
+1 to oxygenated fuel causing issues
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02-07-2014, 01:41 PM
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Cant remember on the plugs but the valve seats were bad. I had one exh valve that was cracked all the way around and the stem was sucked up almost a half an inch. I replaced all valves and a couple seats. I still have the valve and if you shake it it rattles. lol I have never seen one crack all the way around but not drop. Glad I tore it down.
