H2Xmark

reversion is from the lope of the cam at idle speed, hook a vac gauge to your engine at idle with a big cam in it and watch the needle, it's moving around, now bring it up in rpm's say around 2000to 2400rpms and the vac gauge smooth's out, use longer risers that dump the water futher back in the risers and make a smart cam selection and you will not have any problems

Infomaniac

If you are concerned. run just enough water through the exhaust to keep from cooking the rubber. Dump the rest overboard.

rmbuilder

Dyno,
Don't worry about opening the LSA to 112. While you may loose 6-8 hp peak over the same cam ground to 106 LSA , the impact on average hp and torque throughout the range will not be significant. A positive is a broader, flatter torque curve that will make the boat much more enjoyable and easier to drive. Remember reversion is a byproduct of overlap, and overlap is a function of both duration and LSA so both must be considered in your selection.
Bob

JPD Motorsports

Stupid question but what if a person were to take and bypass the water coming out of the exhaust headers and run it into some buns on the pipe its self to keep the noise down, this way the water is on the downwaard side of the headers instead of being collected at the bottom of the headers.

Tinkerer

Info -- that is how mine is riged now. I usually have to change the rubber connection hose yearly.

Hard -- The water doesn't enter the exhaust stream untill after it turns the elboe at the top of the header on manifold type or short tube headers. You need water going through the header to cool it and keep the rubber hose from burning up. The problem is that merc injects way too much water into the exhaust strickly to quiet it down.
Most of the water that is pumped out of the lake doesn't even go into the motor.

Crazyhorse

Dyno, get the stainless pipes to go along with your EMI manifolds, and tell them you want the water outlet nipples at the tail pipe to allow you to run them dry. No water out the stack, no reversion.

dyno

Dave will that cook my manifolds???it needs some water right?

Crazyhorse

No, the manifolds still will have water flow. The only difference is in where the water exits the system. Water flow still exits the manifold via the 1-inch hose from the manifold (you have this plugged on yours because the water passes through the riser gasket) to the stainless riser. Typically this water then exits the stack right at the outlet but nipples can be added on the stack just inside the transom so that the water can be dumped via a thru-hull fitting. The system still runs as cool as before but this way you have dry stacks. Remember that the stainless risers eliminate the 4-inch rubber hoses in your system.

SSComp

Dyno maybe you should get on my list for switchable muffers. If you liked the gauges you love the mufflers!

dyno

bajalion so what you got????? I'm not privy to this subject??