dave911

I recently purchased an offshore with twin built 350 Magnums and Gen 1 Alphas. The motors have GIL Marine headers feeding a Captains Call setup. The motors purrs like a kittens, but I'm not sure how the exahaust cooling is working?

When I go to flush the motors with the captains call ON, water flows freely through the exhaust ports below the drive.
When I go to flush the motors with the captains call OFF, water continues to flow (at a slower pace) through the exhaust ports below the drive, but almost NONE throught the slash-cut tip exhausts?

The engine was thoroughly warmed up when this happened with a temp of 180 degrees. Could it be the rubber flappers in the tail-pipes is forcing water back down through the drive exhuast?

There is some discoloration on the exhaust headers above the curve in the header (before the Captains Call system), which is likely from too much heat?

Other ideas?

Thanks. D911

US1 Fountain

iTrader: (1)

The divertor valves do not close off the lower (thru the drive) exhaust route. It just opens the straight thru transom route in addition. So when your loud, the exhaust goes thru both routes. Same with the water flow. When on the hose, just not enough water volume to flow much straight back. Path of least resistance (down thru the drive)

dave911

Thanks US1. Sounds logical.
See any harm in plugging the exhaust on the drive to get Saltaway into the thru hulls exhaust?

US1 Fountain

iTrader: (1)

Depends. If you plug the lower from the outside, water will still run into the y-pipe until it is full, up to the bottom of the divertor valve, before the water will flow out the transom tips. Might be a chance of sucking some water back into the motor.

Might be best to turn the water up full and raise the rpms higher so the exhaust carries the water out the tips. Give the motors a couple of short bursts. Keep an eye on your garden hose if you do. The higher rpms can suck a hose flat if it is weak, shuting off water flow.

vandeano

I have the same set up and from what you have described mine does the same thing. I wouldn't worry about it. I have been running my boat it in the ocean for years and I rinse well after each outing and use salt away and have had no problems. There really isn't much that salt can damage after that point in the exhaust. Plus it is still getting rinse with water just not as much. Plus most likely your tips are Stainless Steel. No salt will damage that. It will be fine don't take a chance on doing some other damage.

US1 Fountain

iTrader: (1)

I agree.
K I S S: Keep It Simple, Silly

dave911

Good advice, thanks.

wstultz

Simple fix.....Take off the captain's call and throw it in the trash......Done.