End of the season and I think it is time to change the valve springs on the 2001 500EFIs. (300hrs) Last ride out I noticed that once on the trailer that the starboard motor inside exhaust was covered in black on the transom. No notice in loss of power just getting a rich condition on only one side of the motor? My first thought was a fuel issue but generally a fuel failure would result in a lean condition. So I think maybe I have a weak spring. No noticeable loss in power and no noises.
What needs to be changed and why. I understand that the springs lose tenion and need to be switched out. Why would new rockers at 300 ours need replacing? Motors are in an Eliminator daytona 30. To be honest it doesn't see much more than 4500 rpm. The odd time I will run it to 5000 to see the 100mph mark and back off.

It looks like the Isky 8005A are the springs to get. I have sifted through the forums here but most info is over a year old. I am the first to admit, that I do not know car motors but understand 2 strokes great. Just dont want to start changing things becuase "They say" I need to. Looking for good dicussion to better understand how and why here.
Thank you

Rockers need to be inspected thoroughly, but if all is ok they can be reused.
At 300 hours you're a little early but since its the off season,
Pull the heads, valve jobs and new springs, make sure they check the seats (had 2 fall out this month),
Send the injectors out to be cleaned and tested.
Should run as good as new come spring time.

Thank Lil red. Any thoughts on what I am running real rich on one side. Think its a soft valve spring?

Could be but could also be a dirty injector

looks like OEM stuff is real expensive. Springs are $750 vs Isky 8005A at $170

http://www.deepcreekmarina.com/OEMpa...fCOMMON8018649

OK, can some one tell me what the start and finish of the stock 2001 500 EFI springs are. Also I see you can get 15 or 30 shims? Turns out I have a leaky injector which is why I have smoke on the back of the boat.
Going to do the springs but want to know stock specs before I order the isky or the comp springs. Also need to know which shims to order. Any help is appreciated

Talk to Eddie Young, Young performance marine. He has helped many on OSO with this. I need to do it soon too.

anyone?