TOPIC: Should the Butterflies be open all the way at WOT?

1966 Starflite 100. Runs great, a little sluggish off the line but once it planes out it clips along nicely. Maybe a bit cold blooded; rarely starts in the first 3 cranks but it does always start.

#1: Seems to take a long time to wind up to max RPM. At WOT from a stop it takes maybe 7-10 seconds for it to reach max RPM... and that's another thing...

#2: Max RPM is about 4300 at WOT, not within spec for cruising RPM.

#3: The throttle butterflies do not open completely at WOT. In the picture below if the butterfly was completely open, only the edge would be visible. I cannot adjust it open simply with the throttle cable adjustment and I'm a little reluctant to start fooling with the distributer linkage as that's what got me in trouble before.

#4: I do not know the prop pitch but it's a 12.5" three blade. It's slow off the line with more bow rise than I'd like, but it starts to plane out at about 20 mph and then settles down with a minimal wake.

Can I get another 500 RPM or quit while I'm ahead?

Chinewalker wrote:

They should. Looks like you need to do a link & synch...

Mmm-Hmm, so what's the step by step on that? I know about hitting the marks on the throttle cam but I had a devil of a time getting the distributer synced.

OK, so I went through the manual step by step and I think I'm pretty close. Maybe Tuesday I can sneak out of work a little early and get to the lake.

At least this time I was starting with a running engine, I shot a video of all the linkages and marked everything with a sharpie so if it doesn't work it should just be a few minutes to change it back.

Not sure if this was answered? I just went through this though.. the fuel saver linkage needs to be set up correctly..
The magneto has to hit boss on back of powerhead.. set the fuel saver set screw.. butterfly in carb will be 3/4 open or close to.. the little extra left on throttle control will move throttle linkage to open butterfly 100% open.. fuel saver set screw allows linkage to pull butterfly open..

Your Wide Open Throttle rpm should be closer to 5000 rpm. Too much prop pitch for the engine/boat combination. Something down in the 10" - 10-1/2" pitch range should wake it up.

Check your model/serial plate, it should have the recommended operating rpm on it. The high-end of the rpm range is what you're shooting for with WOT and a light load (only the operator on board). This allows the engine to develop rated hp, which it won't do at 4300 rpm.