Sam1647545489 Posted June 28, 2007 Report Share Posted June 28, 2007 Can anyone tell what the hell these things are. The red arrows point to what I am talking about. The large canisters they are attached to are hooked to the exhaust pipe, the exhaust blows into them, and then it runs to the exhaust out of the boat. When I pulled the large canisters off, they had water in them. Anyone know if the large canisters are needed and if I can take them off and run a new pipe out the boat. http://i161.photobucket.com/albums/t214/ls2sam/P6270001.jpg http://i161.photobucket.com/albums/t214/ls2sam/P6270002.jpg Quote Link to comment Share on other sites More sharing options...
SilverEvo8owner Posted June 28, 2007 Report Share Posted June 28, 2007 mufflers? Quote Link to comment Share on other sites More sharing options...
rl Posted June 28, 2007 Report Share Posted June 28, 2007 Expansion chambers? Those are rotax 2 stroke motors arent they? Quote Link to comment Share on other sites More sharing options...
Sam1647545489 Posted June 28, 2007 Author Report Share Posted June 28, 2007 Expansion chambers? Those are rotax 2 stroke motors arent they? They are 2 stroke motors. Purpose of them??? Quote Link to comment Share on other sites More sharing options...
SPLN SUX Posted June 28, 2007 Report Share Posted June 28, 2007 Well you have whats called a wet exhaust. You can run a dry one, but it creates quite a bit of heat, and can cause a fire if not ventalation and shielding is not paid attention to. A lot of the fast boats I.E. Baja's, Cig's, Donzi's, Fountian's etc. all have this... you can see them spitting the water out of the pipes... its a slightly different setup though. As for the valves... they look to be vacuum operated and if i had to take a wild swing in the dark, id say they were used to regulate pressure in the fuel tank some how. i know i see a lot of that in RC airplanes and trucks... they use the exhaust pulse to force a positive pressure to the fuel tank. That and it gave the tank a place to over flow. Perhaps the valve is a one way so that air can go through but fuel cant come out into the exhaust. Honestly w/o knowing the boat and engine, i cant really tell, but i could easily find out. Quote Link to comment Share on other sites More sharing options...
SPLN SUX Posted June 28, 2007 Report Share Posted June 28, 2007 ah its a SEADOO runabout... yea thats your wet exhaust... water from your motor should exit into your exhaust somewhere. Not to be confused with the water from the buildge... totaly seperat system... at least is it on the yamahas. And those vavles are probably what i think they are. You dont need them if you run a "chicken popper" setup. Only the serious RC truck racing guys know what this is Quote Link to comment Share on other sites More sharing options...
HAOLE Posted June 28, 2007 Report Share Posted June 28, 2007 They are 2 stroke motors. Purpose of them??? They tune the power band of the engine. You cannot remove them. The red things are called power valves I do believe... do not remove them either. Your best bet is to just leave it stock unless you can find an off the shelf performance exhaust. I did work on my friends SeaDoo. He had the exhaust get corroded and it ate a hole in the water jacket. We almost sunk the boat in apple valley lake last year. I took them out and welded a patch plate in. Worked good as new Quote Link to comment Share on other sites More sharing options...
Sam1647545489 Posted June 28, 2007 Author Report Share Posted June 28, 2007 They tune the power band of the engine. You cannot remove them. The red things are called power valves I do believe... do not remove them either. Explaination?? I got 2 people telling me opposite things here. Quote Link to comment Share on other sites More sharing options...
Sam1647545489 Posted June 28, 2007 Author Report Share Posted June 28, 2007 ah its a SEADOO runabout... yea thats your wet exhaust... water from your motor should exit into your exhaust somewhere. Not to be confused with the water from the buildge... totaly seperat system... at least is it on the yamahas. And those vavles are probably what i think they are. You dont need them if you run a "chicken popper" setup. Only the serious RC truck racing guys know what this is Explanation on the chicken popper setup? Quote Link to comment Share on other sites More sharing options...
Linn1647545492 Posted June 28, 2007 Report Share Posted June 28, 2007 http://www.rivamotorsports.com/ Quote Link to comment Share on other sites More sharing options...
SPLN SUX Posted June 28, 2007 Report Share Posted June 28, 2007 Explanation on the chicken popper setup? Well the its basically a fuel over flow line that wrapped up in a circle 2-4 times, then bound. It keeps water out, and fuel in, without the use of a valve. Also, the vapor from the fuel is lighter than the air in side, so it actully locks moisture out. I used this on my last wave runner. Worked like a champ, and no fuel spill during a roll over. Thats why i believe they are on there to begin with... an environmental standard... to prevent a fuel dump in the incident of a roll over. Quote Link to comment Share on other sites More sharing options...
SPLN SUX Posted June 28, 2007 Report Share Posted June 28, 2007 http://www.rivamotorsports.com/ Riva parts are A+. We used all there parts on our old 701. Quote Link to comment Share on other sites More sharing options...
SPLN SUX Posted June 28, 2007 Report Share Posted June 28, 2007 Explaination?? I got 2 people telling me opposite things here. Changing the volume is like changing the length of the runners on headers. Quote Link to comment Share on other sites More sharing options...
HAOLE Posted June 28, 2007 Report Share Posted June 28, 2007 Explaination?? I got 2 people telling me opposite things here. 2 strokes must have an expansion chamber in the exhaust. click Quote Link to comment Share on other sites More sharing options...
Sam1647545489 Posted June 28, 2007 Author Report Share Posted June 28, 2007 Ok the valves on top of the cans can be adjusted. The red circles in them are able to tighten and loosen a spring. Would tightening or loosening them change anything... Quote Link to comment Share on other sites More sharing options...
HAOLE Posted June 28, 2007 Report Share Posted June 28, 2007 Ok the valves on top of the cans can be adjusted. The red circles in them are able to tighten and loosen a spring. Would tightening or loosening them change anything... One thing I do know is those engines are very sensitive to changing things. You better get the manual. Quote Link to comment Share on other sites More sharing options...
rl Posted June 28, 2007 Report Share Posted June 28, 2007 I would suggest consulting an expert on the subject, or at least someone who has messed with the exhaust on those boats. Quote Link to comment Share on other sites More sharing options...
Sam1647545489 Posted June 28, 2007 Author Report Share Posted June 28, 2007 One thing I do know is those engines are very sensitive to changing things. You better get the manual. I havent changed anything, I just took off the one canister but didnt change anything. I put it back on and left everything the same. I was just wondering if they were like a catalyc converter or something. Quote Link to comment Share on other sites More sharing options...
HAOLE Posted June 28, 2007 Report Share Posted June 28, 2007 I havent changed anything, I just took off the one canister but didnt change anything. I put it back on and left everything the same. I was just wondering if they were like a catalyc converter or something. no they are not... I would just leave them alone. Is there a problem with the boat? Quote Link to comment Share on other sites More sharing options...
Science Abuse Posted June 28, 2007 Report Share Posted June 28, 2007 In my experience, if you have to ask "Hey, what is this and what does it do?", You probably shouldn't fuck with it. Do EFI boat engines use charcoal cannisters? Quote Link to comment Share on other sites More sharing options...
Linn1647545492 Posted June 28, 2007 Report Share Posted June 28, 2007 no they are not... I would just leave them alone. Is there a problem with the boat? It's not fast enough Quote Link to comment Share on other sites More sharing options...
HAOLE Posted June 28, 2007 Report Share Posted June 28, 2007 It's not fast enough spray it!! Quote Link to comment Share on other sites More sharing options...
HAOLE Posted June 28, 2007 Report Share Posted June 28, 2007 I would start with the impeller. I know that someone has performance kits for those engines. Quote Link to comment Share on other sites More sharing options...
RedRocket1647545505 Posted June 28, 2007 Report Share Posted June 28, 2007 I vote powervalves. 2-stroke dirtbikes run a very similar looking object on them. Quote Link to comment Share on other sites More sharing options...
Lustalbert Posted June 28, 2007 Report Share Posted June 28, 2007 IIRC, those are to control the volume of the exhaust chamber. If you where to modify the RAVE valves on the motor (on the ehaust side of your motor, similar looking device) and change your rotary valve, you could see some more top end, but it would be just like a cam swap where you would lose the bootom end torque. Other things to consider are milling the heads, and re jetting/new chip. Get ahol of the people that race snowmobiles, the majority of the rotax marines are similar, just a longer stroqe to make the torque to spin in water. Quote Link to comment Share on other sites More sharing options...
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