How can I make my boat a little faster?

[Spaceman Spiff]

Here is a closeup

[Spaceman Spiff]

Yeah, that's what I'm seeing as a replacement for my motor. Do you know the location of your pictured rectifier on a 50hp Mercury? Not under the flywheel, is it? I didn't have any extra gray wired, so I used red for the tach signal. I'll have to check for loose connections.

[Spaceman Spiff]

Ok, i got it out in the sun and i can see what's going on a bit. The yellow(or browned now) wires from the stator go to the thing in my picture. Then the single red wire goes around to the switch box. So it must be the rectifier. It's just 3 wires and chassis ground, so the one in Jim's pic should work, right? I went through the parts diagram on marineengine.com and it's show the original NLA one looking exactly like that.

[David - WI]

Yes. There's nothing special about them as long as the amp-rating is higher than your system puts out... 25A bridge rectifier.

https://www.amazon.com/NTE-Electroni...dp/B0002FRBZ0/

[Jim Speros]

The one I showed is a new part in a box.

[Spaceman Spiff]

Well, I went out with my ebay prop and only got up to 36mph. Vented pretty good in the fourth hole and almost no venting in the third hole. I don't know what the diameter is so I'm not too worried the speed. I just hope that the one from Propco that arrives tomorrow does the trick. I should get my new rectifier tomorrow too.

[FMP]

Use a rec regulator to limit the run away voltage at high rpm or you'll probably be buying more tachs.
Use a East Penn marine/ dual purpose type battery.

[Spaceman Spiff]

Even though it runs, it's looking like the stator is the issue. Replaced the rectifier, still not charging and no tach signal. Stator is smoking after running a few minutes.

Now I'm at a crossroads. Is it back to the 70hp on this boat? Or I just found Glastron CV16 with bad motor I could grab tomorrow. I already have a 115 in my garage that would go great on it. Or just replace the stator? Propco prop was delayed by UPS. Hmmm

[Spaceman Spiff]

My stator ohms out at 0.5 ohms. Isn't that the correct value?

[Spaceman Spiff]

I actually don't think this is the right motor to be running at the surface. It can't handle the rpm spike when it vents. I also have an inkling that I'm running more rpm than I thought(like FMP has been saying). I'm going to go a different route. I bought a Tahiti 16' outboard boat for $200 on a nice galvanized trailer. It actually still has the original seats in good condition. Just needs carpet and my Johnson 115 on a jack plate. Hoping for 50 mph out of that setup. I'll make a new thread on that one when I finish redoing the interior on the boat in this thread. I'm painting the interior and putting in some bench seats, and then I'll just fix the stator/rectifier issue and sell it off.

And how awesome is Propco? They are going take the cupped prop back and give me a credit.

[FMP]

There's a triple 85HP 3 carb 80s Force in pieces on a stand, was running fine, going cheap , $150 gets it, in P O.
On Farcebook Force outboard owners site. Low side bullet water pickups, ,2:1 15 spline

Search Daurty Sovyet on FB

Even has a good regulator installed!!!

Lead the horse to water...

[Spaceman Spiff]

I amazed. I added 200lbs of ballast(first mate...LOL) and lost only 1 mph on back to back passes. The boat only weighs 350 bare hull so weight doesn't seem like nearly as much of a factor as 1/4 mile drags in cars.

[David - WI]

I amazed. I added 200lbs of ballast(first mate...LOL) and lost only 1 mph on back to back passes. The boat only weighs 350 bare hull so weight doesn't seem like nearly as much of a factor as 1/4 mile drags in cars.

Or, you're so far from being "optimized" that even 200# doesn't matter... example: if you have enough horsepower to go 70mph empty but you're propped so that your peak hp is occurring at 50mph; then you have excess hp at 50mph but can't go any faster because you're stuck in " 2nd gear" due to the prop.

Same as a car stuck in 2nd gear... you could "pull a house" and still go the same top speed because you're really running out of rpm, not horsepower. (Technically you're out of horsepower because you're past the rpm where the engine makes its peak horsepower).