While you're in there replace the roller lifers as well.

A FRIEND OF MINE HAS A 95 fORMULA 419 WITH TRIPLE 500H.P. CARBURATED. 550HRS NO PROBLEMS.

Panther,

That's a good point I forgot to mention that I could push the middle pin out of all my lifters but one with my finger!

Ditto on what Scott and Panther said.

Friend of mine with a 33 Outlaw broke 3 springs and just replaced those 3. Had around 200 hours at the time. Short time later he noticed a drop in rpm. Went back in and found 25 or the 32 springs trashed. OK. Replaced the whole set. Flushed the motors. Bought a couple of Dominator carbs to put on. Did that and on the shake down/jetting cruise, starboard motor shut down due to no oil pressure.

He is now rebuilding both motors.

DO IT NOW! Regardless of price. Or...

Once I am around 200-225 hours, I plan to have Jack @ Boyd's motorsports go through the heads. I do think though, that all of the above really depends on application, and how the boat is run. An HP500 in a 25' 5,000lb boat run pretty easy on a fresh water lake is quite a bit different than twins in a 33' 7,500lb boat run probably a lot harder in bigger water ( I know I would run it WFO if I had a boat like that ). Point is, I don't think this motor will self distruct if I use it one more time. I really do appreciate all of the comments. I like OSO for a lot of info. and past experiences. I'll let the board know what Master Jack finds out.

if your not that engine savvy, take it to someone that can perform the proper diagnostics and just not guess to replace **** at your cost. most of the time these engines with the 'bad' springs in them had a pwr loss due to float prior to failure. if your not a gear head or have deeeep pockets...keep it stock!

why the hell would you put a dominator carb on this engine!!! WAY TOO BIG!!!!...i know he wanted poor fuel atomization so he could wash down the cylinders and then have to replace the engine in short period of time...

i have never had engine oil in one of my engines for more than 10 hours.

"I changed cams over to the crane 168731 this combo seems to work well and I have seen mph gains across the whole rpm range! "...now how the **** did changing your cam increase your efficiency??????if you changed your prop due to the cam???...then it's the prop....not the cam.

The biggest problem with these engines was with the Gils reverting water. If the idle was high enough, if there was enough fall to the tail (or even a dry tail), then there wouldn't be as severe of a problem with spring breakage. You need to check to see if the engine is reverting water and take steps to correct it. If there are no signs of reversion, then I suppose you could push the replacement off to 250 hours, but why risk damage? You don't have to pull the heads or block to replace the springs, so just do them and be safe.

Yes, the newer engines don't have the spring breakage problem. One of the service fixes is to use the HP500efi spring as the replacement. The newer engines also have the benifit of a computer controlled idle and the cmi headers-which alone will help prevent the breakage problem.

late hp's have a VERY different riser to correct this issue.

To each his own Joe. Someone he knows at Mercury sold him on this idea. But aren't you just a little wrong on this. An engine still only runs at the correct fuel/air mixture that it can get into the cylinders. That's still an equation involving all the intake and exhaust systems. Just like many 350's run a Rochester QuadraJet at 750-800 cfm, but if you do the math on a 350 at 5000 rpm the requirement is only for around 625 cfm give or take. IOW, Mercruiser did the same as he's doing. I all comes down to jetting and mixture ratio. I do think it's questionable on how much return he gets from his investment.

Scott

What are the full cam specs mentioned in this thread, lift full duration & @ .50, RPM range, etc ? I also assume that they are Hydraulic Roller units ?