rpm

I think some of you are missing the real issue here.....

Both 500's run fairly high lift cams and the springs need to be replaced at 200 hours as preventative maintenance, not beause of warranty issues. If you call Mercury about recalls or service bulletins, they are going to tell you NO, there are none. If you ask them about specific recommendations on HP 500 valvetrains, you will get told to replace the springs at 200 hours. Those that choose to run them past those hours are on borrowed time and when one fails and you float a valve and pop the head off and now its costs 6-8k instead of $1,000.00, its not because Mercury put sh$t parts in, its because you didn't follow recommended preventative maintenance. Guys, do yourself a favor - Replace them.

Rod

rpm

From model year 2000 on, both the carb version and the efi version utilize the same spring. Its part # 24-845617A1, so yes it is the same spring.

The issue isn't because its a bad spring, the issue is cycle duty (distance compressed (% of free length) and pressure) load. Even if we built you an engine with the best springs we could find, I would tell you that at 200 hours they would need replaced. This really comes from the spring manufacturers themselves.

Typically the more HP you make, the more spring pressure it takes. Another part of the problem is that the install height needs to remain pretty much the same which means that the spring coils get bigger and will actually be able to compress less without increasing fatigue.

Hope this all helps.

Rod

Scott

The last four posts are correct answers to the question including the part number 929 COMP SPRINGS.

The confusion sets in from the springs they used to use prior to late 99 and 2000 on the carb 500's. The seat pressure was way to high causing premature valve trane component failures. When I say prematuer were talking around 140 hours or so seemed to be the majic number. If you ask Merc why they changed the part number they will tell you that they wanted to have one part number for all three motors (carb,efi +bulldog). I say they should of been held liable but never pushed it with them since my springs and lifters broke right out of warranty I had no case. Crane still offers a replacement spring but I found out from the head people that the pressures were still too high and I think Merc is also now changed over to the Comp Spring.
Just my opinion from my research that I was forced into!!!
BTW I 100% agree with the 200 hour replacement and all of the reasons why i'ts the logical thing to do they are way too cheap compared to pieces parts going through the motor and tearing everything up!! little needle bearings can cause a mess!!! I'm not guessing I know.

h2owarrior

Thanks for the tip guys.....great information.

flimflam

RPM is right on the money, That is the same story I got out of Mecury Racing. I just changed mine @ 234hrs, not a big deal. Look at the price tag of doing it the hard way. By the way Comp springs for $140 and took me start to finish 5hrs, 2000 500hp carb.

LPBoater

had to replace mine. Only 5 sets of springs were still in tact. Here's what I fished out of the oil pan. About 300 hours best I can figure.

WILDTHING TAZ

FOR WHAT IT'S WORTH I RAN WILDTHING OVER 150 HOURS LAST YEAR ON NEW SPRINGS. 1 SPRING WAS BROKE IN ONE HEAD. MOST OF MY RUN TIME IS W.O.T. IN POKER RUNS.IT'S NOT WORTH THE RISK.REPLACE THEM THEIR CHEEP COMPAIRED TO A MOTOR.

BAJA WILL

Great thread, I am at 178hrs on 2001 efi. Guess I will start looking around to get them replaced? So what is a fair price to have them replaced, $500-1000???

Will

frankie

My understanding of the problem was only inherent to the carb 500hp motors. The problem stems from a combination of the cam profile and the earlier Merc/Gil exhaust risers. First issue is that the cam ( I believe ) is ground on a 110 degree LSA. This is too tight of an angle for most marine applications with wet exhaust, they are more prone to reversion on the overlap cycle ( intake & exhaust valve open at the same time). Reversion only happens at Idle .Second issue is the design of the earlier Merc/Gil exhaust risers, they are fairly short. When combined together, at idle the engine would experience some reversion , pulling in a slight amount of water through the exhaust, just enough to create some moisture in the oil. This moisture would make it's way onto the valve springs and over time ( about 200hrs ) would rust them causing them to fatigue and fail. There was also a defect in Crane's factory springs. Once this problem was discovered, Merc has changed the riser design on later model 500hp's, making the pipes "swoop" up higher, this makes them slightly longer before water is introduced into the exhaust stream. They have also changed to the Comp Cams springs. The 500EFI motor has CMI exhaust, a different cam profile and the Comp. springs, so it's not an issue. It wasn't spring pressure that caused the failure, hydraulic rollers run very low spring pressure( about 135-145lbs. on the seat ) this is the same range of pressure that an average perf. hyd. flat tappet cam would run. Solid rollers run high spring pressures because they have much more aggressive profiles and are capable of higher RPM's. It was a combination of design flaws that caused the problem, But you can still change springs every 200hrs, ..... if you want. That's just my long winded .02 cents! Thanks guys!!

frankie

Mike, 1,000-1,100 rpms idle are too high, slamming your Bravo drive in gear at that rpm is hard on the cone clutch and gears. ( even XR's) If you keep your idle at around 800 you'll be fine with the newer style pipes. 500-600 too low . Frank.