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What props for my old Bayliner 800 OMC?

5

5054d

New member
350 Chev, 800 OMC outdrive, 15 spline prop shaft.
Old prop was 15x17 aluminum.

1) Will all 15 spline OMC type props from all engines including large outboards bolt on?

2) Has anyone gone to props like 14.5x18 (3 blade) or 14x20 (4 blade) on an old heavy fibreglass boat?

3) Does anyone have experience/advice on me changing from the 15x17 (max speed attained at 4100 RPM's (hot weather, warm engine) and 4500 RPM's (cold weather, cool engine).

Any info at all is greatly appreciated
 
all OMC 15 spline props are interchangeable except the SX drive stuff. (they're 15 spline as well, but different.)
based on your posted numbers, you have the perfect prop on there already.
Going up in pitch will lug the engine which can damage it.
 
And going down in pitch will just gain you 200 rpm but you won't go any faster it will allow you to load the boat with more people and stuff.
 
Would a 14x19 work nearly the same as a 15x17? Being that the diameter is smaller and the pitch is greater it seems they would balance out to zero net difference.
 
I was thinking I might gain a little speed at max RPM with the next size pitch.
Also if the prop had a smaller diameter I thought it might not fight the water so much for an improved launch when going from idle to cruise speed.
 
only way to get more speed is more engine HP

A really good quality stainless prop might get you 1 or 2 mph, but the risk to the lower unit is rarely worth it
 
the don't call ss props gear eaters for nothing. Want more speed lighten the load gear people. Half a tank of gas instead of full if you can get to where you want and back half a load a gas will do maybe?

Am i right your rpm wot should be between 4200-4600 youi ain't in the zone, maybe you do got too many lbs on the boat.

I don't get the difference in hot vs cold rpm i understand waves slowing you down.

you have what size and type of boat ?
 
Last edited:
Got the message. 15x17 aluminum is probably the best for this old tub.
24' foot, 70's Bayliner, fibreglass, closed cabin, cruiser.
Less weight = more speed.
Aluminum = less problems, (proved that 3 times last year).
Thanks for all the help.
 
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