Offshoreonly.com - 525EFI motor question

Offshoreonly.com (https://www.offshoreonly.com/forums/)

- General Boating Discussion (https://www.offshoreonly.com/forums/general-boating-discussion-51/)

- - 525EFI motor question (https://www.offshoreonly.com/forums/general-boating-discussion/315988-525efi-motor-question.html)

Quote:

Originally Posted by Gladhe8er (Post 4161374)

Put stainless marine headers on and they have been great.

I did the same.

BTW, did you notice any performance difference with the SMs? I haven't concluded my testing yet, but I think I might be down a few RPMs/MPH.

Quote:

Originally Posted by H20 Toie (Post 4161201)

My 400SS with 525's just hit 400 hours, never a problem with the motors,
but just to be safe i just had the top end done on both, turns out they where both in xlnt shape, other than the valve springs that were no longer up to spec,
also as posted before HEADERS
i'm going with the new Hardin marines and never going back to the CMI's
Also you didn't mention fuel pumps, you should have them checked also.

Get your headers now, no way i would trust headers from 2004 even to harbor cruise.

I got a look at those new Hardin Marine headers at the Miami show back in February. I know its hard to tell, but they looked very solid. I hope it's a REALLY long time before I have to deal with headers, but those Hardins deserve very serious consideration. Be very curious to hear your experience with them...

Quote:

Originally Posted by Scott B (Post 4161216)

With all the issues with CMI's, I would yank em and install Stainless Marine in a heartbeat..

And new valve springs :)

i looked into the SM exhaust but they won't fit with my silent call exhaust on the Formula

Quote:

Originally Posted by Dave M (Post 4161464)

I did the same.

BTW, did you notice any performance difference with the SMs? I haven't concluded my testing yet, but I think I might be down a few RPMs/MPH.

Kind of in the same boat as you as I haven't had everything 100% right since the switch. Just got my prop back from BBlades so I should know for sure soon.

Quote:

Originally Posted by shekmark (Post 4161126)

I know you guys must know this. I'm looking at a Formula 370SS, 2005, with 525EFImotors. The motors were built 10/2004. They have 375 hours. Fresh water except for, they said, a poker run in Florida. They have had regular service. Oil changes, water pump stuff. No valve checks. Original headers. What should I worry about with these motors?

These are the items that need to be looked at IMO.

1-Change the springs, retainers, locks and seals if they are even close to 200 hours
2-Check the rocker arms for failure
3-If they are pre 2005 engines, pull the heads, surface them and replace the head gaskets with Cometics and GM head bolts with ARP's
4-Pressure test the headers
5-You can't pressure test the tails but you can run water through them to check for leaks. Also check the dam in the lower portion of the tail for cracks. If that dam cracks, it will allow water to creep up the pipe

I copied and pasted this from a post that I made in the 525 thread that was linked in this thread. If you haven't read it, you really should. It will give you an excellent idea of what needs to be done and what the weak links are in the 525's. All in all, they are excellent engines ( they should be since they are 502's with aluminum heads that makes 550 hp) They just have a few issues that need to be addressed before they become big (read: expensive) issues. If I can help, don't hesitate to give me a call anytime.
Eddie