Jetboat Questions
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Jetboat Questions

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    Junior Member Bert's Avatar
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    Default Jetboat Questions

    I just took a 1979 Southwind tunnel on loan from my parents! I had previously owned a 25 ft. deep V I/O. So I have some questions about the jet drive as it has been a few years since boating on one. We use to go boating in the jetboat growing up and I loved it. The first is it takes a good 20-30 seconds of the engine running in the water before the pump spools up with water. Is this normal? Second the engine has an estimated 550HP with an A impeller. The boat ran 76.1mph at 5400rpms on my Iphone GPS app. Does this sound about right? The boat is a ton of fun. Thanks for any insight in advance.
    Bert

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    Senior Member lbhsbz's Avatar
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    About the pump priming issue...you've most likely got a droop snoot, which is sort of an "S" bent nozzle extention on your jet. This lowers the actual nozzle in relation to the rest of the pump and traps air in the bowl. What you describe is common when using a droop. The solution is to call up Duane at HTP 417 858-8616 and purchase a "prime-a-jet" from him....it's a little automatic bleeder that goes in the bowl.

    With 550 hp, 5400 rpms seems about right. 76mph doesn't seem too far off either....these boats (Southwind tunnels) are all about pump tuning. PM Futs on here...he's the resident Southwind Tunnel king.

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    Senior Member H20MOFO's Avatar
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    Quote Originally Posted by lbhsbz View Post
    About the pump priming issue...you've most likely got a droop snoot, which is sort of an "S" bent nozzle extention on your jet. This lowers the actual nozzle in relation to the rest of the pump and traps air in the bowl. What you describe is common when using a droop. The solution is to call up Duane at HTP 417 858-8616 and purchase a "prime-a-jet" from him....it's a little automatic bleeder that goes in the bowl.

    With 550 hp, 5400 rpms seems about right. 76mph doesn't seem too far off either....these boats (Southwind tunnels) are all about pump tuning. PM Futs on here...he's the resident Southwind Tunnel king.
    For what ever reason.....if I take my diverter handle...and move it up an down. My pump will prime right away. Other wise mine takes quite a few seconds. And yes...that all started with the addition of my droop.
    Another Hot Boat refugee

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    Senior Member bp298's Avatar
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    Quote Originally Posted by Bert View Post
    I just took a 1979 Southwind tunnel on loan from my parents! I had previously owned a 25 ft. deep V I/O. So I have some questions about the jet drive as it has been a few years since boating on one. We use to go boating in the jetboat growing up and I loved it. The first is it takes a good 20-30 seconds of the engine running in the water before the pump spools up with water. Is this normal? Second the engine has an estimated 550HP with an A impeller. The boat ran 76.1mph at 5400rpms on my Iphone GPS app. Does this sound about right? The boat is a ton of fun. Thanks for any insight in advance.
    Bert
    primajet will take care of you're priming problem. performance is in the ballpark, not knowing how much gas/weight/people were in the boat. since you're in the midwest, what's the temp of the water you are running in? pics of the thing, especially the transom area, would help.

    Quote Originally Posted by lbhsbz
    these boats (Southwind tunnels) are all about pump tuning.
    really? i'm all ears, please explain.

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    mo balls than $cents$ IMPATIENT 1's Avatar
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    Quote Originally Posted by H20MOFO View Post
    For what ever reason.....if I take my diverter handle...and move it up an down. My pump will prime right away. Other wise mine takes quite a few seconds. And yes...that all started with the addition of my droop.
    your divertor ain't sealing well brother, in 1 position its not sealin nuff so the air escapes. that or the air pocket gets out easier in the up position in a big burpppppp

    Dare to be different, if it turns out great you can claim you planned it that way.

    Jetboatperformance.com

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    Senior Member lbhsbz's Avatar
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    Quote Originally Posted by bp298 View Post

    really? i'm all ears, please explain.
    I dunno, I think of heard that from Futs a few times.
    Last edited by lbhsbz; 07-16-2010 at 01:16 PM.

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    Senior Member Futs's Avatar
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    Quote Originally Posted by lbhsbz View Post
    I dunno, I think of heard that from Futs a few times.
    That would be hardware my friend.....

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    Senior Member lbhsbz's Avatar
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    Quote Originally Posted by Futs View Post
    That would be hardware my friend.....
    Hm...musta been drunk. Regardless, you're the guy who knows how to make 'em run.

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    Senior Member Futs's Avatar
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    Quote Originally Posted by lbhsbz View Post
    Hm...musta been drunk. Regardless, you're the guy who knows how to make 'em run.
    No BP can tune em pretty good.

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    Senior Member bp298's Avatar
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    Quote Originally Posted by Futs View Post
    No BP can tune em pretty good.
    between the two of us, we might be able to offer some ideas...

    if there were some pics to look at...

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    Junior Member Bert's Avatar
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    Thank you for the responses. Good info. I will attempt to post a picture here. I currently only have two pictures of the boat on my camera. I'll take more of the transom soon. The boat has a Berkely pump, ride plate, droop and diverter I believe. The engine is a 454 11:1 with 565 lift cam.
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    Junior Member Bert's Avatar
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    The other current pic.
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    Senior Member bp298's Avatar
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    nice lookin swtd...

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    Nice looking SWTD!
    I think these tuning gurus want to see lots of photos of the rear of the boat, particularly the jet and it's hardware. Take 'em from many different angles (hi, lo, left, right) cause these guys are looking at the fine points.

    Circ

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