251 prop help

[mkhammer]

Hey JammasterJ,
I got my knee high boots on too. We may have to go buy taller ones before its over.

 

[checkmate632]

wow stalker....for someone with such a bad ass 251 with no pics shouldnt worry about my boat. or you wish yours looked like mine...... i tell you what your b.s will catch up to you on here. like your 27p spinelli that turned into your trying to sell 32 bravo thats on your boat now!!! haha by the way its called a convincor if you have been on 15 you should at least know how to spell it.

Hey nut swinger,for one 86 was one of the worst 25s they ever made,2nd you talk alot behind a computer,meaning you have alot of mouth....3rd what is up with seeing pics?when you see my pics, you and your boy with the tall boots,will see that my stuff is top notch.A 1990 all original gel coat ,with a 900 horse 632,how could that compair to a 86, ragged out,painted,cam2 454,off centered out drive,[because the boat wont go straight]with a ****ty ass stripe down the side....when do you want to trade.sounds like you have the nicer boat of the two.And for the record,im not a good speller,but i can build a nicer boat than you.All you can pick apart on me is how to spell convincor,you are a little bitch..

 

[jammasterj787]

haha you silly paki....im sorry i didnt get a camel painted on my boat. but if your a good sand rat and dont bomb any buildings. i may do it on the next boat i restore. good luck to ya im not gonna reply to you anymore.

 

[jammasterj787]

Well I think I have found my killer porpus issue !!!!!!!!!!!!! restoring this boat I had every part off this thing. I noticed today with the drive up boat on the trailer It pushed down by hand a lil bit. So I lowered the drive down and there was spots that you could move it a lil bit. Turns out there was some air in the lines......... bleeded the lines, no air now and no mush.

it was about 2inch's of movement with trim all the way down!!!!! that would be my not so normal porpus I have had at least that was a free fix.

 

[Big Red]

 

[jammasterj787]

yeah tell me about it Red . I bet the speeds will change a bit now. now I just need a day over 60 deg to go try it out. Plus im gonna pick up a 27p spinelli prop....haha go fig... off of tim on this forum and im gonna buy the 26 bravo from mk when its up for sale. so that should be a good start.

 

[Big Red]

Good ol prop testing you got to love it. I was able to borrow some close by that was a bit cheaper.

 

[mkhammer]

26 bravo prop

JammasterJ,
We are good to go. My 26 bravo 1 is for sale perfect conditon $250 hub not included. You will have to buy a hub for it. I can get you a price on a XR hub if you need one. So let me know when ever your ready.


MKhammer

 

[jammasterj787]

MK I dont need a hub I have 2 that came with the boat when I got it. Im just waiting for a sat or sun thats sunny and over 50 deg so I can at least see what the boat will do with no air in the trim rams and try the 25p mirage I had fixed to make sure im not gonna sell a broken prop to someone. And get some WOT# to work with before I start buying props from people and doing a crap shoot.......................I do think that that motor would be better off in a drag car or jet boat. Too much power in the high rpm and my idle sucks thats my cam mistake but o well. I would say change the cam but I would have to change the heads too back to a 119cc chamber or larger to get in the 9.5 compression range........what to do !!!!!!!!

 

[jammasterj787]

I wouldnt mind looking into a procharger set up. 9 compression range is the sweet spot to be with that set up I think ??? MK any thoughts ????

 

[mkhammer]

I have the prop listed in the propeller dept. on our site. I just put the hubs out there just in case someone needed one. No takers yet.
I like progargers for a lot of reasons sometimes their a little hard to set up. there is not much room in the 253 convincors ,not much room for the intercooler.They have the coolest charge of boost out of any supercharger so it makes more power with less boost and is easy-er on your engine, They build boost with rpm without lag which makes it a lot easy-er on your drive compared to a roots or screw drive blower that make massive torque right out of the gate. Don't get me wrong I like the other blower setups too, An XR drive just can't handle them for long. I totally built my engine with the procharger in mind. Have have done 10 for past customers all but 2 were on stock engines. You can get away with a higher compression ratio 9 or 9.5:1 because of the cool boost. It gets your boat out of the hole better, I run a pretty high lift cam .236/625 int and 245/639 ex on 114 lobe center.
This cam gives it a real broad and even power band, The torque is about the same as a SC600 merc at low end and comes on as hard as you want with throttle, Some guys lock out the advance in the distributor, I didn't, I have a short curve 24deg all in by 2400RPM It works great. I don't know what cam you have but it may work ok too , compression you want around 8.5 to 9.5 to run pump gas.
I have aluminum heads too which helps with heat dissipation, you have to add a few more gages to monitor whats going on, Pyrometer,boost and fuel pressure a must.

Set up right they are awesome and last,

MKHammer

 

[mmhhughes67]

i have a 98 251 with a 540 ci. i run a 26 pitch bravo at 79.2 mph and 5600 rpm. need a 28 pitch. for the bounce mine did the same thing from 30mph to wot, it sucked so, my buddy and i came up with a solution, we made a wedge out of a certain kind of material (top secret,haha) and put them on the most outer edge of the farthest chim at the back. and it cured it 100%. mine was really bad, the boat would actually jumped out of the water. all my buddies have 253's, 259's, and 270's and they all did it, untill we put these on. and NO believe it or not it did not hurt the top end speed. to be honest it feels like it lifts the rear, and airs the boat out more.please becareful with your dry header set up. you are putting alot of heat in that engine compartment that cant excape. i dont want you to have a fire on your hands. it has happened before. if your interested in what we used let me know and maybe we can hook you up with them for a small price. they will already be cut to size, and the right height.

Throttletherapy I own a 92 gtx and have the same problem!!! I'm also going threw the prop game, I would be interested in your top secret fix, just let me know when you can have some available and I'll buy them from you. I also live in md.and will give any thing a shot !