Blazer Marine Slingshot Build!

[Chris Kurtz]

Looking great Mario!
What is your pipe length? In the pictures it looks like its more than 13.5 inches from the face of the exhaust port to the widest part of the pipe. Just wondering if you have experimented with it at different lengths and what you came up with on your engine.
I also converted all my gas boats over to the cable throttle linkage system.
I made one with some music wire but the wire was too small to get a good purchase on with the small set screw I used. I went with the 1/8" flex cable now, much better.
If the small set screws give me any grief I'll just drill and tap them to the next size.

What props have you tried so far?

 

[Mario Johnston]

No issues with it as yet, Rich. I've been removing the motor regularly between run days and loosening the flex at the collet on the carb side, everything seems to be holding up as designed. I'm very happy with this set up!

Chris, I've been running CoCr CC3 props on it. It responds well to the +2, +5 and the +7 prop for the highest top speeds we've recorded so far.
As far as the exhaust, I'm much shorter than 13" from flange to mid expansion chamber!

 

[Chris Kurtz]

Thanks Mario, I'm collecting quite the number of props for the gas boats but I don't think I have that prop yet. I can't seem to find it anywhere.
What is the dia, pitch, and rake? Where do you get them from?
I''m building the Envy gas rigger right now and putting a Gizmo 30+ in it.

 

[Mario Johnston]

Dave Pillado is your man for CoCr
[email protected]

 

[Rich Jones]

Dave Pillado is your man for CoCr
[email protected]

+1 on Dave. I ordered a COCR from him a couple months ago. I had to wait a bit as he was out of the one I wanted but communication was good. The props come out of Australia I believe. It looks really nice though, I imagine I could shave with it.

 

[Rich Jones]

No issues with it as yet, Rich. I've been removing the motor regularly between run days and loosening the flex at the collet on the carb side, everything seems to be holding up as designed. I'm very happy with this set up!

Chris, I've been running CoCr CC3 props on it. It responds well to the +2, +5 and the +7 prop for the highest top speeds we've recorded so far.
As far as the exhaust, I'm much shorter than 13" from flange to mid expansion chamber!
View attachment 290596

Cool thanks Mario. Hey I’ve been measuring my pipe from the exhaust flange to center of the bend, and then from that point straight out to the fattest part of the pipe. Am I measuring that wrong? I’m at 13” as a starting point measuring that way. I guess however you measure you have to start somewhere and end somewhere and note how the boat reacts so guess it doesn’t matter all that much, I was just curious.

 

[Mario Johnston]

I might be measuring it wrong for all I know! This is essentially my first gas boat build so I'm still learning. Troy and TJ Hammons set this pipe length up for me as a starting point with their measurements. I love the way it performs so I haven't thought to change anything as yet

 

[Rich Jones]

I might be measuring it wrong for all I know! This is essentially my first gas boat build so I'm still learning. Troy and TJ Hammons set this pipe length up for me as a starting point with their measurements. I love the way it performs so I haven't thought to change anything as yet

Yeah no doubt, I wouldn’t change a thing!

 

[Mario Johnston]

Update: the boat is still terrifyingly fast, as the engine is fully broken in.
Another image from this past Sundays running, by TJ Hammons

 

[MarkScott]

Now, make a battery box to secure that battery. It was scary last Saturday. Glad it was stuck in that tight turn.

 

[MikeStewart]

Instant paint booth. Sets up in 60 seconds. Bug free finish. $109.00. You'll wonder why you didn't think of it.

 

[Mario Johnston]

Super solid day on the water today!!
Managed a new personal best top speed of 80mph!!! (Tracked boat with on board GPS)
Incredibly happy with this build!

 

[Rich Jones]

So what did you find out from last time? Definitely cooler dryer weather today but there was also some debate regarding your sponson AOA after making that repair. Seems like you’re back in there as far as speed.

 

[Mario Johnston]

The AoA is the same as last weekend when we ran it, Rich. The biggest exceptions being, as you mentioned, cooler temp and running with another boat. Brian and I were both in the water during these laps, the boat saw a bit more chop and loosened up significantly.

 

[Wasted wages]

when you get running by yourself and the water is slick, make few circles inside the course before running the bouys.... make your own chop !! it helps !

 

[Mario Johnston]

UPDATE TIME:
Boat is still an absolute rocket ship!
That is all. Enjoy your day, boys!

More images by TJ Hammons

 

[Wasted wages]

Hi Mario,,,

Now that you have a little run time on it, are you seeing any little problems cropping up ?
Wear points, things getting loose, things you would have done differently?
Any water creep under the clear coat from cracks etc? cowl cracks, wear points ?

Mostly interested on how gas riggers hold up versus nitro riggers over time due to heavier vibrations and weight.

 

[TJ Hammons]

Don't want to steal Mario's thunder, but I wanted to chime in Frank. With the slingshot kit, provided you're diligent with cleaning oil and gas residue after each weekend it will last for years of enjoyment. I drove my kit hard and put it away wet every weekend over 5 seasons, and we run every weekend from the time the water thaws to when it freezes again. I eventually stuffed it in Cincy's black hole between 5 & 6 and cracked the boat in half at the primary bulk head, and the fracture was very much from my neglect. Gas is heavier, but we developed the kit to withstand anything you can throw at it

 

[longballlumber]

I eventually stuffed it in Cincy's black hole between 5 & 6

LOL

 

[Wasted wages]

Hahaha.... didn't catch that ..

Maybe 5-6 am after a heavy night of adult beverage consumption...