raker 19 pitch

[marty f]

would a raker 19 pitch work well with an 115 johnson 2 stroke (1995)?

 

[t.martin]

Re: raker 19 pitch

What kind and size of boat?

 

[t.martin]

Re: raker 19 pitch

disregard previous post. You have the aluminum boat that turns 5000 rpms with a 14x17. I already gave you my opinion. rakers are very good lifting props. You might get more boat out of the water which equals less drag. Just remember RPMs are very important. If you could turn your 17 pitch 500 more rpms you would gain around 4 mph (in theory).

 

[marty f]

Re: raker 19 pitch

so would i loose mph compare to a 17

 

[t.martin]

Re: raker 19 pitch

No. Basically 19 pitch means: every rotation = 19 inches of movement, if you didn't have slippage. You usually have about 10% slippage. I don't think you can turn a 19 pitch 5500-5800 rpms. I think you should go down in diameter but keep the same pitch to get your rpms up to 5500. 13 1/4 x 21 raker. remember this is just my opinion based on my experience with my 115 Fast Strike.

 

[forgot password]

Re: raker 19 pitch

t.martin here (forgot my stinkin password) I'm sorry, but I meant to tell you 13 1/4x17. Smaller diameter but same pitch should give you more rpms, which equals more speed. I wouldn't buy one until you find the right one. Some outboard shops will let you try different ones out.

 

[jimmbo]

Re: raker 19 pitch

no such thing as a 19" raker. Rakers were only made as even number; 18, 20, 22, etc.

 

[walleyehed]

Re: raker 19 pitch

and....dropping diameter does not mean rpm drops too.
There's a bit more to it than that.

 

[marty f]

Re: raker 19 pitch

So Is There A 17 Ptch Better Than The Omc(faster)

 

[burroak]

Re: raker 19 pitch

Marty,

There are so many variables to selecting a prop. I don't think a consensus vote on iboats. com is the way to select a prop. To get a fuller understanding and using info specific to you boat will get you what you want without breaking the bank buying props that don't suit you. Go to www.boatinglife.com/article_content.jsp?ID=10875. It explains the relationship of pitch, diameter, weight of boat, power out of the hole and WOT speed.

The simple fact is, without a variable pitch prop, all you are going to get is a compromise that you are willing to live with when it comes to a hole shot and top end. Kinda' like a marriage, the good with the bad.

 

[walleyehed]

Re: raker 19 pitch

We can pin a prop down relatively close if we have not just engine RPM and speed, but hull type and how you use it and what do you want from this set-up? We need to know where this engine is mounted (which hole) or how the AV plate is in reference to boat bottom.
Faster is easy..it's all in the set-up...problem is..we have to make sure we have a verified accurate tach and we need to look at 5800 as a minumum RPM WOT with the 60 deg V4. We also need to maximize what we have first with "known" variables, then, and only then, can we make a step in the right dirrection.

 

[marty f]

Re: raker 19 pitch

1995 lund tyee grand sport 1750 deep v hull(2,200lbs)1995 john 2 stroke 115 the water intake sits about three inches down from bottom of hull
manu specs call for rpm 4500-5500(wot)

 

[walleyehed]

Re: raker 19 pitch

Very aware of what the manual states...we've tested a bit farther (so has the manufacturer) and we've found on todays fuel, not 1995 fuel when this engine was designed, this particular design is actually lugging if run below or even at 5500. 5200 will ruin this engine on todays fuel...it will build up with coking, carbon deposites, etc, to the point it will ruin the cylinder walls and piston/rings. For BEST over-all performance and engine life, prop for nothing less than 5800 with a normal load....6000 is even better.
By the way..on this combo, a 17P stiletto advantage II, with the engine in the third set of holes from the top will work quite well..this puts the AV plate about 2-2-1/4" above boat bottom.

 

[marty f]

Re: raker 19 pitch

so this will bring up my rpm that much i currently have a 14 x 17 omc part#176214 and its at 5000 rpm wot?

 

[walleyehed]

Re: raker 19 pitch

You'd be better off with a 15P in the stiletto line and raise the engine IF...your tach is correct...
We're running tests with an 1800 fisherman with the same engine, at 3400ft testing props for MWC..the 14X17(OMC) on this rig runs 5750, engine in the lowest mounting position right at 38mph. Although we were testing aluminums this day, I installed a Turbo1 in a 15P, 13-1/4" diameter...speed went to 41.3 and rpm dropped to about 5675.
In this case, I would have to question your tach or the health of your engine....If it's been run at 5000rpm for all of these years, you may have some internal problems unless you are well over 5000-6000ft in elevation.
Your boat is quite a bit lighter than the 1800 DC Fisherman.

 

[marty f]

Re: raker 19 pitch

So Running This Motor Over The Recommended Max Rpm Is Ok

 

[walleyehed]

Re: raker 19 pitch

Yes...If it's not run OVER 5500RPM at Max, you will have coking build-up and eventual problems if that isn't the case already.
You don't have to run it continuously over the 5800-6000 mark, but it needs to be set-up to turn that many R's for the best engine life through-out the total range. You can cruise all day long at 5000RPM if it's propped for 5800 and get 10-20% better fuel economy than propping for 5000 and you won't have any problems due to higher RPM, in-fact, you'll have less problems.

 

[marty f]

Re: raker 19 pitch

just bought a stilleto 17p hope this works!!!!where do you work walleyehead?

 

[walleyehed]

Re: raker 19 pitch

I have my own sales and service facility in NW Kansas.
I also sell stiletto and Turbo....the 17 stiletto is going to drop your RPM some from where it is with your alum 17.

 

[gregtobin]

Re: raker 19 pitch

I have a question about minimum RPMs after reading these posts.
I sometimes cruise around at 1/2 to 3/4 throttle. The slower speed is "more comfortable" for some of my passengers. I've heard that boat motors (mine's a 1979 1150 merc) do well at WOT, so am I risking damage or coking running a partial throttle?

What if I'm trying to troll at 5-10 mph and am using 1/4 throttle?

Thanks
Greg