Goig from17 to 15" pitch. Stay with Stainless?

[surrender]

Have tried everything to bring the rpm's up. 1996 johnson 88 on a 17 McKee craft. 51-5200 max. even raised engine and it only brought them up a little. I have a 13 3/8 X 17 Stainless on now. i would think a four blade 16" pitch would be just right. Get stern out of the water a little more and bring rpms up. Or just a 15" three blade. Should I stick with stainless so I'am comparing apples to apples?

 

[Tig]

Re: Goig from17 to 15" pitch. Stay with Stainless?

Hello Surrender
Have a look at this
http://forums.iboats.com/showthread.php?t=287818
They're going to want all the info.

 

[surrender]

Re: Goig from17 to 15" pitch. Stay with Stainless?

I think its all there:

1) Performance issue you are trying to correct. low rpm's
2) Current prop manufacturer, model, aluminum or stainless and as a minimum. 13 3/8 X17 Stainless(all info i have)
3) Current prop diameter and pitch (required). see above
4) Wide open throttle RPM and speed with an average load (very helpful) 5200
5) Engine/drive make, model, year, and HP 1996 Johnson 88
6) Boat make model, year, length and weight 17' Mckee


All the info was in my original post.
__________________

 

[walleyehed]

Re: Goig from17 to 15" pitch. Stay with Stainless?

Is the engine mounted directly on the transom, as-in "setting" on the transom? (lowest mounting position) 4 bolts thru, take a look and see if the bolt holes are set up to allow the engine to be raised a hole or 2.
This engine must be near perfect on the carb/timing link-n-sync. Static timing needs to be 2degs retarded from max advance value below 1000ft elevation. Are you above that?

 

[surrender]

Re: Goig from17 to 15" pitch. Stay with Stainless?

Thanks Walleyed. Ok, as i said I raised the engine two holes because it was down to far. Can go up one more hole but dont think it would be good. As it is now hole shot suffered a little from the all the way down position. Also, prop starts to ventilate in tight turns. Timing: Did the Reeves method and set at 24 degrees because thats 4 degrees below the 28 it calls for. Thats all per the Reeves method; 4 degrees less using that method. I could set it at 26 and see where it ends up.

 

[Tig]

Re: Goig from17 to 15" pitch. Stay with Stainless?

Just trying to help. I figure a weight weight estimate would be helpful. Maybe not.

 

[surrender]

Re: Goig from17 to 15" pitch. Stay with Stainless?

Just trying to help. I figure a weight weight estimate would be helpful. Maybe not.

I know you were trying to help. Weight of boat from specs is 1490 pounds dry. motor is around 370 i believe. Not much else besides myself and a friend or one of the kids on board.

 

[junior1113]

Re: Goig from17 to 15" pitch. Stay with Stainless?

dont be scared to run that thing to 5500-5800 it will last longer, especially with all this ethanal. id get a vented ss 4 blade 15pitch if it were mine (turbo prop) if your venting in turns motor height is good

 

[surrender]

Re: Goig from17 to 15" pitch. Stay with Stainless?

I'am not scared to run motor that high just want ed to see what people though would work best. So a 15" four blade vented. i'll start looking. in the mean time any other suggestions?

 

[surrender]

Re: Goig from17 to 15" pitch. Stay with Stainless?

I'am not scared to run motor that high just wanted to see what people though would work best. So a 15" four blade vented. i'll start looking. in the mean time any other suggestions?

 

[walleyehed]

Re: Goig from17 to 15" pitch. Stay with Stainless?

Venting in turns is normal if trimmed for max speed.
As for the timing, Joe's method is ok, but I've used 2 degs retarded and tested with the light at WOT (with an experienced driver) and found it to be pretty much spot-on. Turn the max timing stop screw out 1 turn after a trial run and test again to see if there is a difference.
As for the rpm we want as close to 5800 as possible for the minumum.
My 200 'Rude is rated at 5750 MAX...I run 6500-6700 continuous on a regular basis and have run well over 7000 on a few occasions.
A 4 bld 15P "might" gain you 150-200RPM...I would recommend you maximize height with the prop you have, first.

 

[surrender]

Re: Goig from17 to 15" pitch. Stay with Stainless?

Going to try everything before buying new prop. But...can this prop, Yamaha Stiletto 4 blade 15" pitch part number B4415-y1315, be re hubbed to a 13 spline to fit my Johnson? i may be able to get it cheap. If so is it a good prop for my application?

 

[junior1113]

Re: Goig from17 to 15" pitch. Stay with Stainless?

i wouldnt recomend 7000 esspecially on a 88 spl. besides you have a power pack with a rev limiter. walleye must have disconnected his rev limiter or tach is off or maybe high performance parts. my last 88 spl i ran to 5700 and my current 200 hp 3.0 liter i run at 5900 which has the higher rev limiter @ 6700. i wouldnt bother with a yamaha prop.

 

[surrender]

Re: Goig from17 to 15" pitch. Stay with Stainless?

The prop I referenced is really not a Yamaha prop. The part number shows it to be a four bladed Stiletto BAY PRO-I. Not made by Yamaha. The only difference between this one and the johnson one it the hub. Same exact prop. The point is what prop do I put on if I want to get rpms up to 5500-5800? Still have to try to increase the timing a little and see if I can get motor trimmed out without boat porposing. Going to try those things today or Sunday with the 13 3/8 X 17 that I have on there. I really think if i can trim out I'll reach 5300+. That being said i still would need more. So will a 15" pitch do the trick. Dont see going down any further than that.

 

[walleyehed]

Re: Goig from17 to 15" pitch. Stay with Stainless?

i wouldnt recomend 7000 esspecially on a 88 spl. besides you have a power pack with a rev limiter. walleye must have disconnected his rev limiter or tach is off or maybe high performance parts. my last 88 spl i ran to 5700 and my current 200 hp 3.0 liter i run at 5900 which has the higher rev limiter @ 6700. i wouldnt bother with a yamaha prop.

The stock V4's and V6's (carbed) will run into the mid 6000's before reed-float stops it from going any farther. I have no rev limiter (stock) nor does the 88spl. My equipment is used for testing and is in top condition.
No High-performance parts-pure stock other than reeds, which are for better Idle in my use. these engines are just airpumps on needle bearings...they have no mind as to how fast they turn.
The newest Yamaha Props are built by a major prop manufacturer that I highly recommend..maybe 2 years now, but I still feel you need to raise the engine to decrease drag, 1 hole at a time and when you have maxed the set-up start looking at dialing in with a prop.

 

[Randybeall]

Re: Goig from17 to 15" pitch. Stay with Stainless?

But...can this prop, Yamaha Stiletto 4 blade 15" pitch part number B4415-y1315, be re hubbed to a 13 spline to fit my Johnson? i may be able to get it cheap. If so is it a good prop for my application?[/QUOTE]

To answer your question, yes, a Stiletto can be rehubbed to fit your engine. Check with a prop shop about how much it will cost before you spring for it just to make sure it is a good price when you are completed. The 15" 4 blade will give you smoother performance and an increase in rpm. 150 to 200 is what I would expect because the 4 blade will actually transfer energy to the water a little better than three. That prop may allow you to raise the engine that final bolt hole and get a little more speed.( I noticed that you have not mentioned it.) Still going to be below the 5800 the engine spec. but you might look at hull condition and weight of the boat as well. Do you use the engine trim when your doing the testing, trim is an important part of performance. In a tight turn you need to tuck it down to keep from pulling in air, as well as trim it out as much as possible for top rpm.

 

[surrender]

Re: Goig from17 to 15" pitch. Stay with Stainless?

Havn't got back out to test again. Going to trim out as much as I can stand(porpoising). A buddy will be up front to try and stop boat from porpoising so much when i trim out. I report back when thats done.