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First Jetmate added to collection

Z

zappie61

New member
Hi everyone I just bought my first Jetmate last night. I was wondering ifanyone has had one of these and could give me any info on them, mostly how do they handel at hi speed, are they smooth or are they a handful like the Hydro Steams. Where to get used body parts, I.E. I want the hatch cover like the boat for a 100.00 dollors has. Really injoy the site so far, Thanks Everyone.:bigthumb:
 
Parts

zappie61 said:
Hi everyone I just bought my first Jetmate last night. I was wondering ifanyone has had one of these and could give me any info on them, mostly how do they handel at hi speed, are they smooth or are they a handful like the Hydro Steams. Where to get used body parts, I.E. I want the hatch cover like the boat for a 100.00 dollors has. Really injoy the site so far, Thanks Everyone.:bigthumb:
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I would suggest picking up the 100.00 boat for parts---hard to find much at that age.
What engine and jet does yours have?
Post some pic's!!
 
First Jetmate

I am working on getting some pics of it but my son ran off with my camara again. So as soon as he gives it up I will shot sum. I bought without a motor it had a built 455 olds with over the transom headers, the guy I got it from wanted the motor and had to buy the whole boat to get it. So along I came to pickup the pieces. Came out of Cincinnati Oh. The son and I are putting a 350 Olds rocket in it, motor was built for sportsman racing, Balanced and bule printed, 40 over, looking to get a dual carb setup for it, don't know about a tunnul ram yet. I already have one of them for my 77 wiedert with a 460 that I am going to start on, one of these days.
 
For all your pump, cables, steering, headers, or what ever else you need for your drivetrain I recommend Tom Morrow of Smithville MS 662-256-4018. He is good and old school. I used him for all my mechanicals and he knows what a Checkmate is.

My 76 Jetmate runs in the mid 70's it feels like 40 and handles like a dream. Mine has a 455 in it which was a factory engine in this boat. The boat likes to get airborn, on some chop but feels and handles perfect when landing. Good luck on a hatch cover you are lucky to find a jetmate at all. The jetdrive takes a little getting use to at first. When you let off the throttle they tend to coast faster and further because their is no drag from a drive. And no steering unless you give it gas. The way you are pointed when letting of the throttle thats the way you are going unless you hit the throttle again. I recommend a foot throttle helps with the steering. And 1 more thing when you start the boat your moving no neutral.

Welome and glad you found the official Checkmate hang out:thumb:
 

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Olds 350

zappie61 said:
I am working on getting some pics of it but my son ran off with my camara again. So as soon as he gives it up I will shot sum. I bought without a motor it had a built 455 olds with over the transom headers, the guy I got it from wanted the motor and had to buy the whole boat to get it. So along I came to pickup the pieces. Came out of Cincinnati Oh. The son and I are putting a 350 Olds rocket in it, motor was built for sportsman racing, Balanced and bule printed, 40 over, looking to get a dual carb setup for it, don't know about a tunnul ram yet. I already have one of them for my 77 wiedert with a 460 that I am going to start on, one of these days.
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Jets typically loose a lot of power thru the drive, hence the use of very large engines for a relatively small boat. Ask around the jet communitys some, but the largest jet boat I have ever seen with a smallblock anything is 17ft and then with only marginal sucess. you need lots of cubic inches.
Also the impeller will need to be repitched and sized to match the smaller engine. without change from built 455 you may not be able to turn the pump over 3500rpm. there is a hp to impeller trim chart on the berkley jet website.
you could set the impeller to let the engine turn up to 6500 rpm or so, but to load enough water to the pump, you would create a huge amount of drag.
 
My favorite thing about my jetboat was the ability to use reverse as a brake!!
wot to reverse wot does not hurt the drive at all(no change of direction for the drive) and shoots a wall of water straight up behind the boat
that looks really cool!!
What BigRed said about the steering is the gospel truth. must keep some rpm or you loose all steering(ie...no rudder in the water, only thrust steers the boat)When you get used to it, you can spin a jetboat in its own length and slide it sideways to the dock like paralell parking a car!!!!
 
I agree with dave on you will be a hole lot better of running a big block for torque reasons. You can get high HP from a small block but torque is what you need for a Jetboat. Checkmate jets like mine are heavier than most jetboats. Most older jetsboats are all stress cracked out but a Checkmate is built stronger but heavier. If I am correct with out digging up paper work all 455's used in most boats where 68-69 blocks and heads. Mine is a 76 boat and had the orginal engine in it and it was a 69 390hp engine with 500 foot pounds of torque. You need to price the impeller set up before you jump on the small block I think you will be suprised on the cost to change it. If you consider spending the money on changing the impeller and pump parts you will be better off converting to a B.B. chevy. The olds. parts are very high and its not worth the hassel. I can build a 500 caddy engine cheaper than a 455 Olds.
 
I just noticed this post. One thing I wanted to point out was that in a Buick, Oldsmobile or Pontiac, there is no big or small block until you get into the late 70's or early 80's when Chevrolet (corporate) small blocks ended up in everything (the only exception being a Pontiac 301 which was slightly smaller than any other Pontiac, but the mounts are still interchangeable). An Olds Rocket 350 is a full sized Olds engine just like a 455. They are still torquey and if it's built it may have more power than a stock 455. I've been into Pontiacs for a very long time and know that a correctly built Pontiac 350 could smoke a stock 455. There have been some articles on this exact subject in High Performance Pontiac Magazine over the years.

I don't think he would need to change anything in the drive.
 
BullittBen said:
I just noticed this post. One thing I wanted to point out was that in a Buick, Oldsmobile or Pontiac, there is no big or small block until you get into the late 70's or early 80's when Chevrolet (corporate) small blocks ended up in everything (the only exception being a Pontiac 301 which was slightly smaller than any other Pontiac, but the mounts are still interchangeable). An Olds Rocket 350 is a full sized Olds engine just like a 455. They are still torquey and if it's built it may have more power than a stock 455. I've been into Pontiacs for a very long time and know that a correctly built Pontiac 350 could smoke a stock 455. There have been some articles on this exact subject in High Performance Pontiac Magazine over the years.

I don't think he would need to change anything in the drive.
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Not to be rude but, you dont know what your talking about. Olds big block = 400, 425, 455, Olds small block = 307, 330, 350, 403. Theres a 2" difference in deck height between the SBO and The BBO.
Buick has a small block but it is a worthless piece of shit.
You are correct about the pontiac motors and they do make good power, but just as the 2004 small block engine masters challenged showed the Olds By BTR performance made more power.
 
Hey, maybe I'm wrong. I know Pontiacs and most Buick, Olds, Pontiac stuff information is similar as far as that stuff goes.

Are you saying deck height is the only difference though? Deck height is the difference between a Pontiac 301 and everything else Pontiac. The question to me then would be how much power is his 350 making and how much power did a stock 455 make. The parts will physically bolt up, so if he needs to use his engine, and it makes some decent power then he's fine.

Leave it up to him, some of us have to make the best out of what we have.
 
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Deck height and the obvious intake manifold size differece are the most notable differences. Also the BBO has 3" mains and a gas SBO has 2.5" mains. Although The Deisel Olds 350's are the exact same as a gas powered SBO but with 3" mains. The Diesel blocks are probally the most common used in racing applications as theve been proven to handle 1600 hp ( twin Turbo setup)
 
Hey, thanks for the education. It just got me because the Pontiac 301 is the same deal as the small block Olds stuff (wimpy mains and shorter deck - low performance), but no one calls a Pontiac 301 a small block (because technically the block is similar and uses the same transmissions, etc).

On a Chevy Big or Small Block, nothing is interchangeable, and the overall block dimensions are waaaay different so the terminology is obvious.
 
The small block olds should be in no comparison to the 301. The 301 is a turd . I know first hand as i had a 81 formula 3 years ago and quickly replaced the 301 with a 455 Olds. Back to the small block olds Its not a real weak motor at all 700-800 horse can be handles with a billet crank. or for cheaper 600 horse capable, Olds 330's had forged steel cranks and can be used in a 350.
 
No mater what you do to any size engine, there is no substitute for cubic inches. Too get the torque needed for a jet, you need lots of cu in. the biggest boat to be equiped with a small block (read less than 380 cubic inches) was 17 ft...
we had a 18.5 sea sprite with a 302 ford 4bbl and a mercruiser outdrive and we could walk all over the 18.5 ft tri-sonic's with the 390 ford 4bbl with the jet drive. they needed to use a 460 to compete with the little 302
Jets are very inefficient, and require a huge powerplant to make up for it.
 
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