7.5 K&B mod testing vid

[Jim Mamaril]

Hey everyone, just thought I would post a link to a vid of my test session from today.This is an old K&B that I modded,it's the first time I have had it on this hull(Leecraft XT 460) and it seems to run pretty well.I was running a 1450 on 30% Odonnel with a MC 9,then tried an MC 59.Seemed to build a little more power with the 59 but it was a little chilly today.Not sure how fast it was running but guessing low 50's. Unfortunately it was the header that broke in the last run not the coupler.I think with a little more tweeking it will competitive next season,if I can keep it together.Anyone have any thoughts on prop selection?

 

[camaroboy383]

sounds loaded,, try raising the engine i little at a time,,, raise till it looses bite in the corners and come back down a hair... i think you will be happier... maybe try a x442 also...

alden

 

[Jim Mamaril]

sounds loaded,, try raising the engine i little at a time,,, raise till it looses bite in the corners and come back down a hair... i think you will be happier... maybe try a x442 also...

alden

Alden, don't you think an X442 is a little small for a 7.5 ??

Jim

 

[camaroboy383]

the idea here is to unload the engine,, a 442 will do that,,it was more of an example then a real number...im not familiar with .40 size outboards... but im perdy sure the engine can produce more rpm than what was displayed in the video.. try anything smaller than that 50mm... need to unload it as much as possible..

alden

 

[chriscarbon]

Jim,

I would try a x447 before trying the x442 if you were going to do that. Let us know what the prop shaft is in relationship to the bottom of the sponsons i.e set up board. Also, the leecraft web site has good info on the hull. I don't have the link however if someone could post it I would check it out.

Chris

 

[Zach Davis]

Jim,

I would try a x447 before trying the x442 if you were going to do that. Let us know what the prop shaft is in relationship to the bottom of the sponsons i.e set up board. Also, the leecraft web site has good info on the hull. I don't have the link however if someone could post it I would check it out.

Chris

Here is the site:

http://www.leecraftracing.com/home.htm

Zach

 

[Jim Mamaril]

Jim,

I would try a x447 before trying the x442 if you were going to do that. Let us know what the prop shaft is in relationship to the bottom of the sponsons i.e set up board. Also, the leecraft web site has good info on the hull. I don't have the link however if someone could post it I would check it out.

Chris

Here is the site:

http://www.leecraftracing.com/home.htm

Zach

Zach,Thanks for the link,I have been thru this setup many times and have set my prop height approx 3/16 th above my sponson bottoms.

Chris,Alden, You are right it does need to unload a bit,I had this hull set up for my stock Redhead motor and did not change anything when I bolted this one on.I have had good results with this hull prop combo but will try some smaller props next time out,maybe start with an x448 and then an x447 or even maybe a 230. I have found that you have to get a prop with just the right amount of lift or it will porpoise and not get enough air in the tunnel to transition to a smooth ride. I just need to get a header made so I can get back on the water and test some more.Thanks for all the tips guys.

Jim

 

[SayMikey]

Is your 1450 back cut? Get a Mark Anderson 1450 from Gary Pruesse most guys are running it or a similar prop

 

[opio]

Jim we need to find a bigger test pond during the summer lol!

 

[Jim Mamaril]

Jim we need to find a bigger test pond during the summer lol!

Jeremy, We definately need to find a bigger pond especially with the faster boats. I did some more testing today,raised the motor about an 1/8th, backcut on the 1450 and lentghened the pipe about a 1/4. I know it sounds like it is loaded on the vid but when you are there it is really singing. In this vid I handed the remote to Matt and let him have a little fun,infact he was driving when it blew over. I definately saw an improvement over last week.I was mistaken about my prop depth last post,It was actually set about 1/16 below sponsons.I think I can still go a little higher but I dont want to get it to loose for race water but I will keep raising it until it's to loose then drop it a bit.

 

[camaroboy383]

that looks much better...looks like she's cookin... go higher,,,go higher...lol...

alden

 

[Rick Sowell]

1450 back cut, that is a 20 tunnel prop, can't that thing pull anymore prop than that? just kidding you Jim, looks like you are getting faster.

 

[Jim Mamaril]

1450 back cut, that is a 20 tunnel prop, can't that thing pull anymore prop than that? just kidding you Jim, looks like you are getting faster.

Yeah its cooking along pretty good now,guessing somewhere in low 60's maybe hi 50's. On the second run I was seeing how well it accelerated as if you were coming to the start line and it has much better throttle response since I lenthgened the pipe.I could have leaned on it a bit more but figured better rich than lean.I really need to get it on a full size course and let her stretch her legs a bit and see what she has.Hey Rick are you going to the record trials next weekend??

 

[Rick Sowell]

I plan on being at the record trials and the fun run both, are you going to be at the trials? if so I'll see you there

 

[Jim Mamaril]

I plan on being at the record trials and the fun run both, are you going to be at the trials? if so I'll see you there

See you there.