two stroke outboard in engine well

[cicatrix]

Hello,*

I have a problem I am hoping someone will have an answer to. I have purchased a 2001 Jonson 6hp outboard. It is installed in a engine well in the lazorette of my hobie 33 sailboat. The problem I am having is that when the engine is running the exhaust from the upper exhaust port (5/16 hole on back of engine).* Is filling the cockpit with exhaust. This engine also uses a underwater exhaust system so I guess I'm wondering why it has the second exhaust port ?* Also is it possible to plug the upper port or re route it ?** I have done some digging but have no good results. Installing a blower in the lazorette is not an option as this is a racing boat and weight needs to be kept

Thank you



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[SolingSailor]

Re: two stroke outboard in engine well

I'm a little out of my element here, so hopefully others will contribute. I have sailed in company with 2 or 3 Hobie 33's, and they have all had outboards mounted on transom brackets. This would allow them to at least get the leg out of the water while racing, or stow the outboard below. Is your boat modified with an engine well? Regarding a second exhaust port, the smaller engines have an idle bypass, which should allow only a small amount of exhaust with some spitting water, because at idle speeds there is not enough exhaust pressure to overcome the under-water pressure. Can you post a picture of your outboard well?

 

[cicatrix]

Re: two stroke outboard in engine well

There is alot of snow on the boat right now but I will try and post a pic soon. The Hobie 33's you are thinking of are modified. The "stock" Hobie 33 has an engine well in the Laz. The engine is attached to an arm and is able to lift up and store in a horizontal position while sailing. There is a plug that fits in the hole while the motor is up. I think most Hobie's came with a honda 7.5 but im not 100% sure.

 

[sloopy]

Re: two stroke outboard in engine well

I've done this. It may run funny at idle but will not hurt the engine. The exhaust holes just go into the skeg it allows the exhaust to vent when there is not enough pressure to push it out below the water. I just used some duct tape when I used to sail on a melges.

 

[steelespike]

Re: two stroke outboard in engine well

Even though the Honda is a 4 stroke I would think the exhaust would still be pretty obnoxious.
I would think the idea is you only run the motor when you could make some speed.
It may be difficult to start and may require more rpm to stay running.
If your just idling I would think the fumes would still float up into the well whether you plug the holes or not.
You might want to be sure the fuel ratio is correct and that the fuel pump diaphram is not leaking fuel into the crankcase.
50:1 is still pretty smokey in a confined area.