HydroSCREAM is alive...

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It floats! It sits pretty good but it could use 50 pounds up front in the nose. My other issue is even with the Jack plate all the way up and the trim all the way down the exhaust is about half in water and half out. With the extra weight up front it should raise it. But I am thinking of a shorter mid and or fabricating the exhaust to exit upwards.

Nice to get out and make sure the steering was bled properly and all the gauges were reading perfect. Only two issues were add weight to the nose and the exhaust. Aside from that it sits pretty good! Got a video coming just loading it up.


"Life is Fun" the graffiti was suiting lol




Helmet just incase lol

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Better shot of the rear...







Video after it was up to temp...


http://www.youtube.com/watch?v=qkfnRT7FB3s


I like me these 2 strokes!

[77viper]

Looks like it sits pretty good. I wouldn't worry too much about the exhaust being under water. With my viper I can't take off with the trim all the way down or else it buries the nose.

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Hey Chet, My offshore exhaust kit is blocked off to the prop and just exits through the square exhaust. When it get submerged I think there is to much back pressure built up. I gave it 3/4 throttle and it didnt have any jam to get on plane so I decided to not try and kill the motor. I know when this looper was on my 19 J-Craft at 3/4 throttle she had tons of jam.

I think I might have to cut the offshore kit off and TIG weld it higher up, only problem is then I dont have any exhaust expansion.

Any thoughts man?

[77viper]

In stock form all the exhaust comes out through the prop well under water so if your exhaust is exiting 3" under water it's still less back pressure. I have never done any testing so this is just a theory.

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I know the thru prop exhaust would be designed as per manufactures specs to the motor compression etc... Thing is when I trimmed up the motor a bit to get the exhaust above water and I gave it some gas it was really responsive. Then when i trimmed it down and the exhaust submerged and gave it gas to plane it didnt have the jam.

I'm not to sure whats going on, but I wonder if moving the exhaust up would helps it breath. Only drawback I can see is the exhaust wont have as much expansion area. Another idea is to take a Suzuki GSX-R exhaust actuators and set it in the upper mid. That way it can open at idle to relieve pressure at low rpm, then close when the boat is up on plane.

I'm confused here on what to do first... add 50 pounds to the nose and hope it brings the stern up a few inches. Or move the exhaust up closer to the power head? One member on Fast Boats Canada suggested to drill (2) 3/4 inch holes in the upper mid to help it relieve exhaust pressure when submerged.

[jacklake2003]

You mean it won't get on plane at all with the exhaust submerged? If so, I think maybe there is another problem; fuel mixture, fuel delievery, etc. I guess the above water exhaust is really effecting how it runs, it sounds like it's running a bit lean. I would probably just go back to stock exhaust, but I'm sure you can get your set up to work with a little more tweaking. I would shy away from adding weight or drilling any more holes. Good luck and keep us posted! - Chris

[silkeysak]

I am running a 225 looper on a Viking. I ported the exhaust on the lower unit old school style and did not block it off through the prop. It comes on a plane great with no ill effect on hole shot and everything is submerged. Just my opinion, but like Jacklake I think it must be someting else. The motors were designed to have the exhaust submerged. Have you checked the timing on a dyno? I had a similar problem that lead back to the fuel pump. Check the line that gives the air pulse from the block for leaks, and go from there. Also carburetor bowl floats might not be adjusted right, starving it for fuel causing a lean condition, like jacklake was saying. It sounds like it's starving for fuel. What size looper is it?

[coupe]

I think your onto something. I have a rude 2.6 liter that when trimmed all the way down seems to "flood" a little bit, when I trim up, it "cleans up" some. I always thought it was the float adj.....just too lazy to fix it.LOL.

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Some good info here guys I appreciate all info, sometime when you are trying to figure out some problems other peoples info helps you not to get tunnel vision on one issue so to speak.

Well after talking to a Mercury Tech today he has given me some insight on this exhaust situation. He said to contact Land and Sea to see if they have had any situations like this and also to see it perhaps this exhaust kit was supposed to block the exhaust passage to the prop completely.

Also he had said these Looper motors are extremely hard to tune because of the 3 jets per carb. He brought up an interesting point about when the exhaust is submerged when trimmed down. It is most likely loading up the cylinders and running extremely rich. When i was trimming the motor up to get the exhaust above the waterline and gave it a shot it was responsive and had more power.

I am going to try a little experiment and see if it works because it will tell me right away if this Exhaust is the problem. I am going to make a Square plate out of Aluminum and cut a 2 1/4 inch hole in it and TIG weld a 2 1/4 aluminum round pipe to it. I'll bring the exhaust up above the waterline and go back out and try and plane. If the boat gets up and goes, I'll get a factory OMC mid and call it a day. If not...I have lots of gas cans and and a **** ton of matches!!! lol