Prop Slip or ??
 

I have a 1995 Wellcraft Eclipse 196. It has a 2005 310 h.p. Crusader 5.7 and a Alpha One Gen 2 Outdrive.

Bought the boat cheap to play with while I work on my Formula 242 SS. The first two attempts at taking it out were ended by a fuel issue that ended up being a small piece of debris getting sucked up into the screen in the fuel pickup tube which let enough fuel through for the engine to idle for hours but only about 20 seconds of run time before the carb bowl was sucked dry. Fixed that.

The third attempt at taking it out resulted in verifying that the fuel issue was solved after a few minutes of run time but the distributor pickup decided to crap out so adequate fuel is pretty irrelevant without spark. :lolhit:

Ended up replacing the distributor and took it out today for the first successful (relatively) run. It did not break down, we did not need to be towed back, oil pressure was good, temperature was good, so it was a good couple hours.

Heres the issue, at 3200 rpm the boat goes 30 mph. Not any noticeable increase or change from 3200 to 3500 but when I try to throttle past 3500 engine rpm will move to 4000 but speed falls off. You can watch the tach move up to 4000 and you feel it nose over and hear the engine tone change.

Thoughts?

either the prop hub or the engine coupler is slipping.

How would I diagnose either of those?

Also, what would be a good prop for that setup?

Mark the outside ring of the coupler and the input shaft with a white paint stick. Take the prop of and mark the hub and prop same way. Run it and see if they moved. With a bad coupler, you usually see/smell rubber.

A 3 blade Laser II in 17 or 19" pitch would get you in the ballpark for a good starter prop. A 17 or 19" pitch High 5 would also likely work.

That hull will respond well to a 17 pitch stilletto perhaps a 19. With a 5.7 it should be a 60 mph boat if the engine is in tune and fresh.....55 if she's a turd.

Engines good. 170 compression across the board, no blow by at all.

The marina that dewinterized it claimed 58 mile an hour at 5300 rpm on their test run. All I have changed is a distributor since the pickup went out on the other one and was on backorder. Timing is at 32 degrees at 3000. Was going to play with timing but a bad shift cable bellow was letting in more water than I was comfortable with so didn't want to sit around floating for long. Going to try to fix that tomorrow and try it out again with a different prop and the coupler marked on Sunday.

Should timing be different than what its at now?

Upper cone clutch slip? Does the RPM jump up quick under load at high RPM? Like a few hundred RPM all at once?

Baja170 - he has an ALPHA drive - no cone clutch.

is the prop clean, no dings etc......

Crap. Thank you for pointing that out. I have terrible eyes and probably should not post from the phone.

Umm.... It was that day. Not so much after it got into the ramp while pulling it on the trailer. I'll post a pic, should be good for a laugh.

It was an aluminum prop and did have some bends to it previously but it was hammered and dollied out very nicely. Just a few very minor chips in the edges, tip of your fingernail size.

I have a 21p SS Mirage I can throw on it. I'm guessing one of the 27p Mirages off of the Scarab wouldnt be a good choice right?

If it is an aluminum prop it could be blade flex. Are there any flex lines on the blades?

How to set the timing depends on what ignition and possibly what ignition module you have.

I think your main issue is a prop issue.

Mallory YLE624AV Distributor and a regular ignition coil. No other module. Set base timing at 10 degrees, ran it to 3000 rpm and saw 32 degrees. Didnt run it any higher though. Most systems add 20 on top of base I believe.

Rev it until the timing does not advance any more and then set it at 32-34* total.

You have a hammmered on alum. prop, Find yourself a decent 21p stainless mirage or similiar, a little looking you can pick one up used for 100 bucks. Next question,,,What effect does drive trim have on the problem?

I have a SS 21p Mirage sitting on my desk. Gonna throw it on after I replace the shift cable bellow.

Trim seemed to have no effect on it at all.