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Lolly
08-04-2004, 12:27 PM
Hi

I just bought a 1990 MC tristar 190 with an Indmar 351 240hp and 1:1 Borg Warner velvet drive. On fresh water with 4 people on board I am maxing out out 4200rpm and about 40-41mph on fresh water. I thought the operating rpm is around 4500-4600 rpm. Prop is OJ 13x13 Nobral in excellent condition and engine sounds like it's running smooth, quiet and great. :)

So, am I running right ?

1. - If so, is there anything I can do to increase speed without sacrificing low end?

2.- If not does the engine need service or what ?

Thanks

Lolly

T Scott
08-05-2004, 08:49 AM
My neighbor and good friend has an 88 Tristar withthe same setup you mentioned. He gets 42-43 with only him in the boat. If you are getting 41ish with a full load, I'd say you are doing pretty good. I wouldn't think it would be worth the time or money to invest in a new prop or engine mods to get you an additional 1-2 mph. Just my 2cents.

stevo137
08-05-2004, 09:03 AM
Hey Lolly,
I had the same set up on my 88 Tristar. Did 4400 rpm 44-45 mph. My speedos were rebuilt and calibrated. I used an Ambush 13x13 4 blade. It blew the original 13x13 Nibral away. That boat screamed!
I would be interested to see what that Acme 3 blade would have done for that boat. Different boat though, I put the same 4 blade on my 93 Prostar and I lost top end but the performance is a good trade off.
I going to try the Acme next.

east tx skier
08-05-2004, 10:23 AM
www.acmemarine.com. Get the number from this site and ask to speak to Bill Weeks. The cool thing about acme is that they will recommend a prop based on your situation, not just based on your boat engine combo. Who knows, other prop makers may do this, too. I dropped a little pitch when I got my acme, which offers a little more out of the hole. I didn't lose any top end. They are extremely helpful though, and have me as a very satisfied customer on their hands.