Going forward on this, I am going to:

1. Pull and inspect the plugs. Might also run a compression test just for grins, but it had 175+ PSI on all holes right before it was dropped in.

2. Check throttle linkage to make sure secondaries are opening all the way.

3. Examine fuel system including tank pickup. Will mount a GoPro pointed at fuel pressure gauge to track that during water test.

4. Increase jet sizes. Can't hurt, and might prove to be my issue - better safe than sorry.

5. Double check timing. Question - can this be done in the driveway on a hose? I have a V8 22 HP500 module on there now, and was thinking about trying a V6 module to allow more initial timing for better dock characteristics.

Anything else I should add?

You can check the timing on the hose. Just try not to hold it too long while reving checking total timing.

I keep staring at the fuel pump you have online. It's just pi$$ing me off looking at it. :frog:

Just curious, what made you purchase that pump? I know zero about them, but it just seems like not the pump I would use on a 600HP marine engine.

Do you know if the pickup on the fuel tank has a one way valve? I have twin IMCO tanks on my nordic and 1 of the valves was sticking. S**T canned both and upgraded from 3/8 - 1/2 ID AN without check valves and sweeping -10 90's.

I do agree that fuel pump is likely totally wrong for your setup. Put one of those on my fathers 260 merc and as expected, it runs well, IMO different story on your motor.

Found the specs on that pump after digging all over.

50GPH flow at 6psi? :rolleyes:

http://fme-cat.com/overlays/part-det...ine&brandId=CF

just browsing thru my holley book. They list the "red" electric pump to flow 71GPH, at 4psi. MAx HP Naturally aspirated, 425HP.

The holley blue pump, 95GPH at 7psi. Max HP naturally aspirated, 550HP.

Holley black pump, 120GPH at 9psi. MAX HP naturally aspirated 750HP.

Jetting will be a waste of time until you get some fuel to the carb.

Budman, I think you are on the right track. Did you read fuel delivery thread over at Boatfreaks? Mechanical pump was recommended to me, that should be an easy choice for you given you have the pump provision. I ****canned my siphon valves as well.

MT, it's the same pump my friend has been running on his boat with the 500HP. In fact, I believe he was running one for several seasons with a 509 / B&M 250 setup. Maybe he just lives a charmed life and I don't. :p

I guess the fuel pressure gauge will tell the tale - hoping to run it on Sunday; probably my last gasp until the really cold weather settles in.

Still thinking about switching to the mechanical pump, but will probably need a special bronze or composite pushrod for the billet cam. Apparently these come with their own headaches, as outlined here:

http://www.offshoreonly.com/forums/d...lobe-flat.html

I also dislike having a mechanical pump hanging off my block, as it makes it a b!tch to get to the seawater pump to change impellers. If I have to upgrade the pump, it's going to have to wait - tapped out right now. Maybe Santa will bring one. ;)

Mild considering the above info on the intake manifold, is there one that you recommend for safer operation on a carburetor 502 stock?

stimleck has another one of those "distracting" avatars, but on a whole different wavelength than MT's. I doubt if you would have much luck hitchhiking with a thumb like that.