Prop Question and Tranny Question

[Jackman]

I was wondering...since I'm getting my 454s rebuilt and when you rebuild you usually get a jump in HP....Will the HP jump be enough to require a change in props from what they are specd'd as per the owners manual (ie original design). If so what do you suggest? I'm not really looking to make a speed boat out of it. I'd rather prop it to make the engines last and the fuel economy change for the better.

I'm going to closely examine the velvet drives while I have everything out. Since I've owned the boat one of the drives whines while in reverse. I'm contemplating replacing the trannny pump since it seems that maybe the pump is on its way out. I'll probably replace, at a minimum, both shaft seals as well. In addition to looking for metal is there anything else to look for? The fluid condition in both drives is perfect..not burnt. I understand that these trannies are built tough and don't have to rebuilt unless someone has destroyed it.

[67HAT34C]

SUSPECT YOUR TRANNIES ARE 1.88/1 AND YOU ARE RUNNING 20X21X3? WHAT WAS YOUR PERFORMANCE BEFORE? KTS AND RPM'S

SHOULD BE ABOUT 4400 RPMS FOR MAX EFICIENCY AND CRUISE AT ABOUT 70-75% OF WOT. BEST THING IS TO TRY IT OUT. YOU CAN REPITCH THE EXISTING PROPS ABOUT 1-2 DEGREES UNLESS THEY WERE DONE BEFORE. IF YOU ARE RUNNIG AT MORE THAN 4400 THEN TURN THEM UP A LITTLE.

ALL OF THE B&W'S WINE IN REVERSE, IF YOURS IS NOT OVERLY LOUD THEN IT IS MOST LIKELY 0K. EITHER WAY A MINOR OVERHAUL ON BOTH UNITS WOULD BE A GOOD IDEA SINCE THEY ARE OUT.

[Jackman]

Well...

The props I got with the boat were cut down quite a bit. The set I have on now are 18.5 by 20. The spare set even smaller. It sounds as though I may be due for a new set of props. Any ideas? Stay three-bladed or go four.

You are correct about the trannies and I know wot should be 4400. Don't know what it will be with these props and the rebuilt engines but I suspect they will be turning too fast. I used to be able to go, before I had the problem, 24to25kts wot and cruise 17-18kts.

[davesommers]

Jackman,
Your rebuild of the gas 454's will probably not net you a significant increase that would require a repitch on the props. It will just give you reliablity, allow you to turn the engines to the rated speed and get a bit better economy.

If you are going to replace the shaft logs I would suggest the PSS dripless seals. They are really dripless and have worked well in my 36.

The velvet drives are generally very durable and I have run them several thousand hours in past boats. They fail like other marine gears; clutches, bearings and seals give out. If you are not slipping, no excessive noise when running and not leaking oil from the seals they are probably ok. On my old boat the 72 series always whined a little in reverse, not real loud though. I had them reworked at American Marine Trans in Edgewater MD at the second rebuild of the engines at around 4k hours due to leaky seals. They did great job on them for me and have a trans dyno that can check the condition etc...
Sorry no magic answers - good luck.

[34Hatt]

As in the other post above he nailed it with the dyno.
While have mine out I had them on a dyno at a local marine transmission place in Deer Park Long Island it was $75 ea and they check pressure shift points check for leaks and can tell if they need anything mine we fine so put them back in two year later still going good.
Dan

[hattitude]

I am running 19x19 4 -blades on my 32'

[Jackman]

"I am running 19x19 4 -blades on my 32'"

Are you diesel or 454 gas? I'm staying gas at the moment or longer.....If you are running the 4-bladed props what are your economy specs like? I was thinking maybe my boat couldn't handle 4-bladed props. What's your WOT, cruise and milage?

Thanks

[hattitude]

My 1983 Hatt is powered w/ '93 gas 454 mercruisers.
She cruises at approx. 17 knots at 3100 rpm with a
fully belly of fuel. This is an increase of 1.5 knots
since the installation of trim tabs. Prior to the tabs,
she burned 24 gal/hr at that rpm. The 4-blade props
are a true 19x19. They seem to be quieter and
smoother than the 3-blade. She also comes out of
the hole quicker. I've been monitoring your story, and
I agree with your decision to stay with the gas. I'm
surrounded by larger boats and seasoned captains who
strongly urge me to stay with the simplicity that this
little 32 offers.
Mike