Help, any Ideas?
 

2000 342 Performance. 2 years ago, rebuilt Starboard 502. It is like new, runs perfect. This spring I rebuilt the port 502, by the same shop that has been around for years and years with a great reputation. Sounds and runs well but will not make the same top end. WOT Starboard RPM 5000, Port RPM 4500+ almost 4600. We have checked everything and are out of ideas.



Help please

Thanks

Lenny

I would start off checking fuel pressure, timing and take a look to see what the spark plugs look like.

List the "everything" that you checked.

fuel pressure, timing, new plugs,fuel injectors redone,switched tacs, switched ECMs, checked the prop. Thinking about switching drives. going to change throttle cable.

Swapping drives will do nothing unless one of them has external damage.
Make sure the throttle cable is adjusted properly. Pull the flame arrestor and make sure the the throttle body flap is going to WOT. Unless the cable is hard to move, changing it will do nothing.

Did you check fuel pressure while running at WOT??

Fuel regulator was replaced with an adjustable one. A gearhead friend says it should be 40PSI. it is set at 44psi at idle.

So the answer to you question is no. Not checked at WOT

43 psi is the stock setting and it should maintain that at all rpms. It needs to be checked while running the boat in the water under load.

I will try to get that done this week. any other ideas?

Another avenue to look at is the props....i had one prop from a set that were supposed to be 23p each......problem was that one prop had blades closer to 24.5P and it was loading the motor down too. They must have been worked at some point but you couldn't tell just by looking at them

Nice thing abt having 2 engs is you can swap stuff around to troubleshoot. I would start with ign components; coil, dist, external spark boxes if applicable.

Make sure spark plugs and gaps are the same between engs. 0.035" would be a good place to start.

This

Swap props from side to side and run it( your shifters will be backwards)
and see what it does