78 HYDRASPORT 17.9 150HP V6 PROP HELP

[tawas23]

I bought a 78 hydrasport bass boat 150hp v6 and need help finding correct prop the charts say 19 pitch and kinda proven as I had 2 props to try first was a 23 cleaver @ 4500RPM WOT other was a 21 pitch @ 4750 RPM WOT so 19 falls into this as charts recommended so what 19 pitch prop would fit best for this boat any help is appreciated though a laser but not sure

 

[Bondo]

Ayuh,.... What's the Wot rpms Supposed to be for yer motor,..??

 

[jbcurt00]

Tawas, please.dont start multiple topics about the same subject. Deleted the duolicate topic

 

[tawas23]

OK NP my WOT is 5500 RPM

 

[QBhoy]

Laser 23? have her well over 60 gps, decent hole shot and RPMs spot on...even with gear onboard.

 

[jimmbo]

Which 150hp do you have, Mercury, OMC, Yamaha, or Suzuki? Also what year? If you know, what is the WOT rpm range?

 

[David Young]

'If' your redline is 5500, looks like a 19 might be the best one.

 

[QBhoy]

I?m thinking something isn?t right here. No way should you only be pulling those revs with a 21?. That set up should be screaming way up the Rev range with a 21? and would normally call for even a 23?.
Presuming you are trimmed up at WOT ? If you are, I?d guess your tacho is way out or you need to check your engine function.

 

[QBhoy]

What does the GPS suggest in speed ?

 

[jimmbo]

We need to know what the engine is, in order to determine the gear ratio it has

 

[tawas23]

ok the outboard is a 79 MERCURY 150HP V6 and compression is all 120 to 115 in all 6 cylinders and after putting this info in Mercury chart it recommends a 19 pitch prop in all chats I have found that is correct with my thoughts about the 19 pitch so hoping I can get a second opinion on a laser II 14 x 19 prop with pvs plugs out boat is really light boat at 800/1000 lbs motor seems to run great at idle and at all RPM ranges also sounds like it running really good too.I believe the gear is a 1.87 .serial numbers is 5130069.the rpms will go up some at trim but not @ 5500 where it should be and I can feel it wants to go up but can actually feel the load on the boat is to much prop on this 21 pitch at WOT. also kinda slow getting on plane but I dont hammer it when taking off either.so hoping to agree a 14 x 19 laser II would be good choice on this info .thanks for all the help too.Also the 23 cleaver was 15 x 23 and the other was a 14 x 21 so both were consistent with Rpm changes when changing pitch. so hoping to be right where I should be with the laser II 14 x 19 plugs out.Asking if this would be a correct prop to get for the set up mentioned??

 

[jimmbo]

23 Cleaver 4500rpm
21 unknown 4750 rpm
Cleaver props are stern lifters and are great props for competition tunnel hulls where the risk of the boat catching too much air will flip it over. But are not the best choice for bass boats


Chopper Props were popular on bass boats in the 70s and early 80s, these were bow lifters. They had the ultimate venting, Over hub exhaust.



You have to prop it for WOT. Over propping and trying to unload the blades by using the vent holes to get respectable HoleShot will still result in too low WOT RPM. The Merc V6 is not lacking in low speed torque, when propped for 5500 rpm.
Your numbers so far will indicate an rpm of approx. 5200 - 5300 if you get a 19". Engine setup, as in height, will have some effect on acceleration and rpm

A Laser II is often used on fishing boats, but it has very large vent holes and running it without any restrictor plugs may result in serious blowout on acceleration.

My personal preference for a prop is Mercury's Enteria. It has shown to be a very good prop in a variety of applications. But like with any prop YMMV

 

[tawas23]

Yea I knew the cleaver wasn't a good choice just tried it for pitch reasons and took it off and ran the 21 but knew that wasn't correct either so I will check my prop height and make sure its not to low .I have a laser on hand in the 14 x 19 pitch and at WOT I should be closer to 5400 /5500 .I just called Mercury and said this laser should work if I use the plugs start small and move to medium if necessary but should work and also said check prop height too thanks

 

[QBhoy]

I?d imagine you won?t need any plug venting with a 19? prop.
Still think something doesn?t add up. With that gear ratio, power and weight of boat....a low 19? pitch, to me seems way low. Unless you have loads of weight on the boat all the time.
I?m familiar with more than a few 17-19? boats (most heavier than this) with 150?s and 175?, and they all have at least a 23? Laser or similar. Usually run around 60mph. One of them (a marshan 19) has a 150 mariner, same ratio and runs a 25?.
I suppose your numbers are what?s best to go off. Maybe you are at altitude or the hull just maybe isn?t a fast hull, like I had imagined.
All the best.

 

[jimmbo]

That is a crankrated 150 hp. In 1986 it was reintroduced as a prop rated 135 hp. So when comparing it to other 150s going 60 mph, make sure it is an apples to apples comparison. My 2008 150hp Ficht was able to push my 18ft deep bee bowrider at 55 mph with engine mounted about 3 inch up and 5 inch setback and a prop that could run partially submerged. Altitude was about 2500 above sea level

 

[QBhoy]

A fine point Jimbo. Was just reading back there. This engine will likely be the straight 6 in line 150 ?
The engines I refer to are V6. Even still. Maybe reckon a 19? still a bit low. Hard to tell or imagine without seeing it go. Even with 130hp. Should still fly and scream with that boat, when trimmed up ?

 

[QBhoy]

I used to have a Ring 18 boat. She had a 150 V6 and latterly a 200v6. They both had the same laser 2 23? on them at one point and the 200 at one point a 25? Both ran over 60mph. The latter, well over. Perhaps due to the race derived narrow hull, but I?d imagine the posters boat is no slouch when set up right.

 

[QBhoy]

No Title

Of course the spotty decals made all the more quicker !

 

[jimmbo]

A fine point Jimbo. Was just reading back there. This engine will likely be the straight 6 in line 150 ?
The engines I refer to are V6. ?

1978 was the first year of the V6 150hp. the old inline 150 of 1977 was relabeled the 1400, so as not to have 2 150 hp in the line up.


To the OP: You have tried a couple of props, at least one of them was totally unsuited for your application. From what I know about 'Bass Boats' they can have the engine mounted higher on the transom, then using a suitable performance prop, get very good top end performance. If you plan to use the boat for skiing/wakeboarding you will need a different engine height to ensure the prop has a good bite, but slightly lower top speed.

 

[Faztbullet]

Need OP to post picture of boat as the 17.9 could be a offshore or could be a bass hull. If the bass hull we rigged them with a 20 Turbo.