Dirthead

Has anyone ever had any luck with the shotgun exaust sclincers from Drew Marine? They claim to help with reversion. Their web site is http://www.drewmarine.com/

The Menace

Installed new engines in January and ran for about 2 hours and had no issues. One engine then developed a slight leak after an additional 1.8 hours of moderate running at cruise speed, milkshaked with only about 1/2 quart of water.

Becasue it was not climbing the stick and pushing out the top we knew it was only a very small leak.

We changed oil and filters and again picked up about a quart of water in 120 miles of straight running. (we did stop a couple times and check for significant volume increases)

We pressureized the block and found a very, very slight leak in the head gasket. The water was dripping into the valley. The only way we could tell was to remove the intake and just watch and watch and watch.

We removed the one head replaced the gasket with some additonal sealer, wiped everything down in the valley and under the valve covers as much as possible and we were off!

3 very knowledgable people looked at it with their various opinions. If we would have listened to the first two we would have purchased new headers and still had the leak. A little more due diligence paid off.

Dirthead

Expresscat39,

How did you pressurize the block with water while you had the intake removed?

Bill272

I had some water issues with my last rebuild. One issue was a leak in a exhaust riser stud that was replaced with a helicoil and not sealed. The other was just a low idle speed. From what I learned then, I'd say there's no way you should be idling down to 400 RPM. I was getting reversion idling at 500 rpm on hp500's. Now I make sure I'm at around 800 and have no problems. It does force me to have to only put one engine in gear to maintain no-wake speed, but it keeps the water out of the engine.

Dirthead

My marinia said that I should not shift a 1995 Bravo 1 drive at any RPM's much more than 600 RPM's. They told me that i would risk tearing out the couplers/ gears/ clutch if I do. Any ideas on this?

Bill272

No ideas really. My mechanic said to keep the r's up. I have the Merc engine manual for my 95 HP500's (actually HP425-800SC) and it states that the recommended idle (in gear) is 750. I would assume that Merc shipped most of those engines with Bravo I's. Maybe someone else has some better input on this

PatriYacht

I think at one point Merc recommended 800 idle to help with reversion problems on early HP 500's with the low risers on Merc/ Gil manifolds

PatriYacht

You could block the water passages with a couple of ground flat pieces of crs (cold rolled steel) clamped in place with large c-clamps.

Waterfoul

Sure sounds like a reversion issue to me. I would agree with the do not idle at 400 rpm theory. That is really low for that cam configuration. 800 rpm is shiftable on a Bravo drive... been doing it at 700-800 rpm for many years on mine.

I'd try your test again with the lowest idle setting being 600+ rpm... maybe even 700+ rpm and see what happens.

'Foul

Ron P

Doesn't your boat sit low in the stern? Level may not be the best angle for testing.