Sport .20 setup issues

[Hydro Junkie]

It could be that the air into the carb wasn't impeded in the same way it can be with a cowl installed. In a way, a cowl can work like a restrictor plate between the carb and intake manifold on a NASCAR engine

 

[Grimracer]

again.. make sure you don't have an exhaust leak into the cowl.. (got that T-Shirt!).. boat ran just fine without the cowl.. but put the cowl on and..........after a few laps.. it would slow.

Grim

 

[Bradley Maglinger]

Thanks Bradley, great info.

What do you mean by deck clearance?

Also, I measure my pipe from the exhaust port, not the glow plug.

The heat thing makes sense, but I was surprised that it ran so much better without the cowling. Any thoughts on why that would be?

I meant Head clearance, and I do measure from the side of the case in then middle where the plug would be centered to the center ban of the pipe. All of my boats run better without a cowling as well. Here is the Best advice I can give, change 1 thing at a time. You will get it figured out. I also agree with Grimm check for exhaust leak.

 

[Jarcaines]

No exhaust leak that I can tell? The coupler is fine, exhaust runs all the way out the transom. I’ll double check for anything that looks iffy when I get down to LA next week. (My boat is already on the way)

 

[FloridaScaleBoater]

No exhaust leak that I can tell? The coupler is fine, exhaust runs all the way out the transom. I’ll double check for anything that looks iffy when I get down to LA next week. (My boat is already on the way)

Exhaust out the transom, how far is the run from the pipe stinger to the transom?
What size tubing is that exhaust extension?
Are you SURE it's sealed well where that extension attaches to the stinger?

 

[Jarcaines]

Exhaust out the transom, how far is the run from the pipe stinger to the transom?
What size tubing is that exhaust extension?
Are you SURE it's sealed well where that extension attaches to the stinger?

I’ll have to measure all that when I get to LA, but it runs through a muffler before the extension. It all should be sealed fine, but I’ll double check. I did get some pipe wrap, so I might wrap the joints too just to make sure.

 

[FloridaScaleBoater]

I’ll have to measure all that when I get to LA, but it runs through a muffler before the extension. It all should be sealed fine, but I’ll double check. I did get some pipe wrap, so I might wrap the joints too just to make sure.

The ID of the extension needs to be 2 to 3 times larger than the stinger. Depending on length of extension.
If too small it creates back pressure which creates heat.

 

[James Schmidt]

I don’t have the same sport 20 you do but I have the beta and I fought my Hydro for a very long time with some of the same problems you have. Mine would surge and never get on the pipe or stay on the pipe.

Like Mark was talking about 8 1/2 inches at least a little longer doesn’t hurt I run mine at eight and seven eights.

I found that if engine is surging it was running to Rich. And Bradley is right about restricting the water and fattening the needle you’ll burn more nitro but you can go to far in that direction too. If you do it will surge as well.

Another thing is it that motor likes a little bit a load don’t run a wimpy prop.
my favorite props are the ABC 1515 ABC 1516 and Octura m440. I am running my head button clearance at 10 thousands. Not to say that the clearance that I run is the right clearance but in my boat.my engine likes to be a little looser

 

[Jarcaines]

Here are a few pictures I have of the setup. There is a third 2oz hopper tank under the deck of the sponson that has since been removed (was running out of fuel early in the process, so I added that. Problem has been fixed). Other than that everything is basically the same.

 

[Samuel Hagan JR]

Do you have any fresh air getting in your boat for the motor? Looks like the cowling is completely sealed.

 

[Bradley Maglinger]

Do you have any fresh air getting in your boat for the motor? Looks like the cowling is completely sealed.

On the sides of the cowl it has openings.

 

[Samuel Hagan JR]

On the sides of the cowl it has openings.

Is it enough? He said it runs better without the cowl. Might not have enough air getting in there.

 

[Hydro Junkie]

I was thinking the same thing since we all know these engines need plenty of air. That was why I made the statement comparing a cowl to a restrictor plate

 

[James Schmidt]

Man, that’s a killer Sport 20 I like it!!!

 

[Wasted wages]

Man, that’s a killer Sport 20 I like it!!!

I agree...very nice setup!! Would love to try building one of these... lots of room inside the hull,,, nice and wide too!!


Getting back to the issue, as someone already mentioned, go 1 step at a time.. throwing a bunch of changes at it may fix it but you won't be the wiser to what ultimately fixed it.

I would try my sponge idea first .. cheap, easy and probably something that should be in the boat anyway...
then move on to fuel issues to look for leaks etc. (both air or fuel) clean your filters...
then to air starvation issues,,,
then heat issues...pipe wrap, reduced water..
If you have a spare needle,, put it in the water feed line and start dialing it down..

Maybe try some different fuel,,, prop up or down,,,different pipe lengths..

Good luck and keep us updated on what the problem was,, once you sort it out...

 

[Samuel Hagan JR]

Part that sucks is trying to figure it out at a race. Good luck to you at the Nationals. Keep us posted.

 

[Jarcaines]

Part that sucks is trying to figure it out at a race. Good luck to you at the Nationals. Keep us posted.

Right?

 

[Mike Cathey]

I have found that if you have a leak in the muffler in or out you will find castor oil inside the boat. I broke in a new 67 motor at home today and I had that situation. A short piece of 1/2" tubing between the pipe and muffler and between the muffler and the 1/2" brass pipe that goes through the transom took care of it.

 

[SayMikey]

Is there a hole in the transom to let water out? Make sure your water lines are not letting water in boat.Same with the head oring

 

[Grimracer]

if there is any oil in the boat after a run.. you have an exhaust leak..

Grim