merc 500

[glashole]

on the merc 500 (carburated mid 90's) what is a good rule of thumb as far as hours between rebuilds?

this would be based on looking at a used 35-38ft go-fast style boat

for this arguement lets assume it was used mid to aggressive for a worst case scenario

Shea

[Carl C]

Fixx, same with the 525? How about just replacing the springs and lifters without pulling the heads?

[VetteLT193]

For the top end rebuild it can come as soon as 200 hours. I think that is what my brothers had when he bought it and it needed a new cam as well. he upgraded to the crane 731. keep in mind parts aren't cheap on these things either.

[Carl C]

OK, I've got another season or two I figure. I think I have the new style headers and pressure tested them once.

[Carl C]

"carl,the newer style headers have about a 1/2'' of the inner tube showing at the flange where they bolt to the head before they weld the outter tube to the inner tube.."

Yes, I have that. Sorry about the detour, Shea.

[glashole]

no prob carl, I got the info i needed

now we can discuss the ticking time bomb you have in the back of your boat.............:)

[RickSE]

I'm at about 260-hours on my 500EFI time bomb. :wink: I'm probably just going to go to Aluminum heads when I go into mine.

[Carl C]

"I'm at about 260-hours on my 500EFI time bomb. :wink: I'm probably just going to go to Aluminum heads when I go into mine."

I think the ticking time bomb referred to the CMI headers......

[VetteLT193]

And don't forget the EFI's are different than the Carb engines. Seems like the first rebuild on the carb flavor 500's (assuming HP 500 and not 500 bull dog) should come around 200 hours. EFI's have a longer life span and I think the carb version after the first rebuild would follow that same time span if the cam gets upgraded. It seems like the original 500's had a bit of a weak combo of valve springs and cam and after the first update life is better.

[The Hedgehog]

Fixx is right. There are a fee minor differences between the hp 500's and the 500 EFI's but you still need to do the heads and bottom at those basic intervals. 500's are great. I have a set in the Fountain and have seen Tex run the snot out of one!

[gcarter]

Aluminum heads at that point sounds like a good idea anyway!