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Discussion Starter #1
This is my first jet boat. Just bought a 94 Cheyenne 19 tunnel. Has a 468 solid roller dart pro 1 heads jesel belt drive 13.5 to 1 comp and a 1050 dominator. Supposedly dynoed at 680 hp. It is a berkly jet with droop. Just tore pump apart. Has Alot of play in it. The impeller is bronze cant find any markings on it. Also has an inducer. Took it to river and top speed only 80 and seems slow take off. Turns 6200 and raps to around 7300 on take off. Previous owner claimed 106 mph. Don't know if I believe but figured in the 90s. Am I wrong or is something wrong with boat and what to improve speed. Thanks for any help.
 

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Retired Air Force
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106 mph is possible but the pump set up needs to be right. Pump work, the right shoe and ride plate angle can make a big difference in top speed. Find a good pump guy to help. Ease in to the throttle a little at the start rather than letting rpm slip up so high
 

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I think an impeller and wear ring should give you 10 more .... man that thing is beat ...
 

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Blown, OHBA Member
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Nice ride. Your a lucky man. It took me 30 years to get a Cheyene but it was worth the wait.

I am running 82 with a 496 at 5900 with an A/B impeller, and like you I want it in the tripple didgets. A friend is helping me set up the pump. He had me drill and tap the the pump housing for pressure readings in two places, One at about 7 Oclock and one at about 11 Oclock. The way I'm understanding it is i'm shooting for around 35 to 40 pounds of intake pressure at wide open throttle. If you not showing any pressure at WOT then the pump is starving for water. The pressure readings help you determine if you need to add or remove shoe or loader. If I'm understanding what my friend has told me then the reading from the bottom port is for shoe and the top port is for loader.

At this time my pump tuning is on hold as I am changing from naturaly asperated to blown for next year and no sense tuning the pump twice. Do a search for the things you have questions on, theres a lot of smart people and good info here. Don't be afraid to ask questions, even dumb questions have saved time and money in the past.

Oh yes take that impeller to someone that can check it out for you, it might can be saved. A good wear ring and impeller is a must. Picking the right one is the trick.

Good luck and welcome aboard
Don

PS where you located?
 

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Discussion Starter #7
Thanks I will do some more research on these things. May go ahead and send impeller off so will know what it is and if it's still good.

There are two holes with plugs on the back of the pump. Is that where I need to read pressure from?

Was thinking about rebuilding pump my self. Have worked in machine shop for a while and doesn't look to bad to rebuild. But I might be mistaking.

In north Florida just south of Tallahassee
 

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Thanks I will do some more research on these things. May go ahead and send impeller off so will know what it is and if it's still good.

There are two holes with plugs on the back of the pump. Is that where I need to read pressure from?

Was thinking about rebuilding pump my self. Have worked in machine shop for a while and doesn't look to bad to rebuild. But I might be mistaking.

In north Florida just south of Tallahassee
I think those holes you are talking about are for oil
 

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Blown, OHBA Member
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Thanks I will do some more research on these things. May go ahead and send impeller off so will know what it is and if it's still good.

There are two holes with plugs on the back of the pump. Is that where I need to read pressure from?

Was thinking about rebuilding pump my self. Have worked in machine shop for a while and doesn't look to bad to rebuild. But I might be mistaking.

In north Florida just south of Tallahassee
The plugs on the bowl are for oil as GA Jet stated. the plugs in mine I put there for taking intake pressure readings as I make changes in the shoe and loader. your pump will not have them unless another owner put them there for the same reason.

Rebuilding your pump is not that hard to do. I would call Tom at Jet Boat Performance he will have everything you need to do the Job right. He is one of the best ones here to talk to when you need help, and he is always willing to help.

Sent you a PM (private message)
 

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"This is my first jet boat. Just bought a 94 Cheyenne 19 tunnel."


Man, you got one helluva boat on your hands! Especially for a first jet boat. Don't know your previous boat experience, but know that you've got a boat that will pucker your a-hole in an instant lol. Be careful getting to know her. That boat is more than capable of the triple digits you seek, and yes, you need to go through the pump. But more than just a rebuild, it needs to be setup properly. Is there a bump, or "bubble" on the keel just ahead of the intake? Didn't look like in the pic. Also curious what (if any) shims are under the shoe. Not to beat a dead horse but be careful running at those speeds until you've got some seat time to recognize when to lift...stay safe. And congrats on the purchase :))THumbsUp
 

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Discussion Starter #11
Thanks for keeping the info coming. Seems like y'all try to help out Alot on this forum. Yes I have been pretty fast in some outboard boats all pads but this is the fist tunnel boat. I bought the boat because I'm a major gear head and have been building BBC engines for a while. Who needs a 2.6 merc when u can have well over 600 inches strapped behind you. I was kinda hoping to get in this thing and shut all my local outboard buddies up but not happening right now. Maybe with all of the help from here it want be long.

There is a little hump that runs down the boat in front of the loader but not sure if that's what your askink about. I'll post a little better pic. I don't think there is any shims either.
Thanks again guys.
 

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It would be great if you had any info on the history of this boat, specifically who laid it up and rigged it. Usually Tommy (Tom Papp, maker of the boat) would flip the hull over and put a spoon shaped "bubble" on the keel that tapered into the intake. Yours does not seem to have that. Not a big deal, can be added. It will help keep the pump loaded. Also, doesn't look like there is a pop-off valve. Running those speeds it should have one. Take your time, ask questions, etc. There are a lot of fans of that hull on here, a lot of guys that race them and have set them up. Congrats again. A little time to get her set up and you will be smoking your buddies boats lol:)devil
 

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Blown, OHBA Member
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It would be great if you had any info on the history of this boat, specifically who laid it up and rigged it. Usually Tommy (Tom Papp, maker of the boat) would flip the hull over and put a spoon shaped "bubble" on the keel that tapered into the intake. Yours does not seem to have that. Not a big deal, can be added. It will help keep the pump loaded. Also, doesn't look like there is a pop-off valve. Running those speeds it should have one. Take your time, ask questions, etc. There are a lot of fans of that hull on here, a lot of guys that race them and have set them up. Congrats again. A little time to get her set up and you will be smoking your buddies boats lol:)devil
I talked to him last night for a while on the phone, a very respectfull young man that deserves all the help we can muster up.

He said he would post up the hull Id letters so we could ID the builder. From the looks of the pics I don't think this boat has a race keel. Not all were built with them, that I believe was an option you paid more for. Also looks like the shoe is droped down a half inch or more to catch some water, I don''t know but that seems a bit on the low side to me. May be that way to compensate for the lack of a race type keel.

Didn't think to ask if the boat had a Jet Away, pop off, or a low pro intake for that mater. Mabe he can post a pic of the pump on the inside for us.

Come on you guys with tunnels, chime in here and help this young man out with his first jet. You know some one here would help you if you needed it.:)hand
 

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"Need For Speed"
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I talked to him last night for a while on the phone, a very respectfull young man that deserves all the help we can muster up.

He said he would post up the hull Id letters so we could ID the builder. From the looks of the pics I don't think this boat has a race keel. Not all were built with them, that I believe was an option you paid more for. Also looks like the shoe is droped down a half inch or more to catch some water, I don''t know but that seems a bit on the low side to me. May be that way to compensate for the lack of a race type keel.

Didn't think to ask if the boat had a Jet Away, pop off, or a low pro intake for that mater. Mabe he can post a pic of the pump on the inside for us.

Come on you guys with tunnels, chime in here and help this young man out with his first jet. You know some one here would help you if you needed it.:)hand
IMO, the first step is to know the first three digits of the S/N so we can verify who constructed the hull There are a couple of variations of the keel from manufacturer. Also if we could determine the layup, being is it a lake or race and what the hull weight may be. I am going to guess it may be a lake layup as it appears to have a radius keel, but not a drop keel. The next area will to determine what intake is in the boat. The intakes generally varied by who constructed the boat. Take a good look at the intake inside the boat and see if it has any identification. Agressor, Alpha? I don't see shims in the shoe, all I am seeing is a 1/2" shoe, which would be a normal starting point.

Once these items are determined, then a plan of action can be addressed. If you do want to run high speed, a drop keel is probably in your future. Where are you located geographically. We can probably help get you in contact with a knowledgable glass man that can assist with this part of the project.

Wild hair, you are doing a good job in answering this fellow's initial questions and offering him some good direction.

Gear
 

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Discussion Starter #15
Ok I got the hull numbers. Jbx19657f394

Maybe that will help some. I also looked at the keel and it doesn't look completely flat. Looks like there is about a 2 inch drop. but y'all might call that flat. I'll include a little better pic.
Not sure about the shoe but don't see any shims. I'll measure the ride plate angle when I get the pump back together. Don't know the weight either. And wild hair it does have a jet away and the shaft only looks to be about 9 or ten inches.
 

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Blown, OHBA Member
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Wild hair, you are doing a good job in answering this fellow's initial questions and offering him some good direction.

Gear[/QUOTE]

Thanks

After 35 years of fooling with these old jet boats I thought I knew a thing or two. Then 3 years ago I found my way here, and found out I didn't know squat.:confused:

In three years I have learned a lot, But I'm still learning stuff here every day. There are some wise ol birds on this web site. (There are some real dumb shits to). I found this is one place you can stick your nose in someone elses business and survive as long as your not disruptive, might even learn something along the way. I wish I had this site 35 years ago. Hell I wish I had a computer back then.:happy: :)hand
 

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Blown, OHBA Member
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Ok I got the hull numbers. Jbx19657f394

Maybe that will help some. I also looked at the keel and it doesn't look completely flat. Looks like there is about a 2 inch drop. but y'all might call that flat. I'll include a little better pic.
Not sure about the shoe but don't see any shims. I'll measure the ride plate angle when I get the pump back together. Don't know the weight either. And wild hair it does have a jet away and the shaft only looks to be about 9 or ten inches.
Your boat was built in Oklahoma by Firehawk Performance boats.

Oklahoma Boat Manufacturers

I won't swear to it but Jimmy Johnson comes to mind, I think he use to have Jet boat enginering out of Gore Okla. I'm not positive he is the builder Just that his name is what seams to stick in my head in relation to Firehawk.
 

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The Man
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Your boat was built in Oklahoma by Firehawk Performance boats.

Oklahoma Boat Manufacturers

I won't swear to it but Jimmy Johnson comes to mind, I think he use to have Jet boat enginering out of Gore Okla. I'm not positive he is the builder Just that his name is what seams to stick in my head in relation to Firehawk.
JBX should be a Jimmy Johnson boat. My Youngblood is a JBX boat as well.
 

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Discussion Starter #19
Thanks for that info. Learning more and more everyday. Is this a well built boat. Or are pretty much all of the Cheyennes the same no matter who built them.
 

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Blown, OHBA Member
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Anything new going on with the Cheyene? Pump parts in yet? :)hand
 
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