At wits end...what would Jim do?

[Tony]

Thats what floored me, why 5 and 6?? Tomorrow Im gonna back off the rocker nuts and leakdown the cylinders.

[MOBILEMERCMAN]

5 & 6 are on opposite banks. Chevy is 1,3,5,7;2,4,6,8. Ford is 1,2,3,4;5,6,7,8.

Thanks for previous explanation. I know the are opposite. I was wondering which two cylinders join in the intake for the exhaust cross over. I don't know if his heads are blocked or have that provision. But it could be one leak crossing if they are the joining cylinders. Its probably 3-6 or4-5 though.

[fbc25el]

I chased the same problem with water in exaust. I found out in my case that on the hose the exaust would not get hot enough to burn off the condensation. After i ran the boat on the lake no condensation.

[Geronimo36]

Thats what floored me, why 5 and 6??

5 and 6 have a straight shot down when you look into the manifold.

Are you sure the tailpipe is sealed to the exhaust manifold? In addition to the gasket, Stainless Marine also also supplies you with a high-temp black RTV to put on there, it seals very well.

I once worked on a triple engine 45' sonic where due to an exhaust leak at the manifold/tailpipe joint on the center engine it reverted water back into the manifold. Those tailpipes were almost 5 ft long before the water entered the pipe. It was a humbling experience because I didn't think the water could revert back that far from an exhaust leak. So nowadays I don't rule anything out!

[Chris]

There's no water in the SM junction. It bypasses the connection with a hose.

Leakdown may not tell you what you're looking for- especially if your cracks are on the backside of the exhaust valve seat and in the bowl. You need to pressure test the cooling jackets.

[FULL FORCE]

The heads are new.... right?
sure it's not condensation?

Pretty much seems like every other possibility was covered..

[Tony]

Are you sure the tailpipe is sealed to the exhaust manifold? In addition to the gasket, Stainless Marine also also supplies you with a high-temp black RTV to put on there, it seals very well.

Yes, I used the silicone

You need to pressure test the cooling jackets.

Did that last night, plugged off one of the exhaust manfold riser lines and stuffed a pressure testing manifold in the other. I then ran the hose until water was ****ing water 20 ft. out of the test rig, shut the valve on the rig and let the water hose pressure build up about 15 psi on the guage, then shut off the valve at the sea strainer, then added 10psi of air on top of that. It held 25 psi on the guage and 30 psi on my dash guage for well over an hour. The thermostats are drilled and the mechanical water line going to the dash guage comes off the back of the intake manifold by the distributor. I even opened both remote block drains and both remote cooler drains and let water p!ss out of them, I know the entire water jacket was full of water and evenly pressureized.

[erierunnin]

3 more days, get er fixed

[FULL FORCE]

Hmmm.. this is a tuff one...I am having a hard time coming up with suggestions...

[Geronimo36]

There's no water in the SM junction. It bypasses the connection with a hose..

Chris, the associated exhaust/air leak if the junction isn't properly sealed will cause reversion, believe me.

[Ratickle]

When we're done with this, the reversion issue caused by leaks is intriguing me.....

[MOBILEMERCMAN]

After the cooling pressure test I think its time to look back at the tailpieces and flappers. If it was just condensation I would expect both motors to show signs. I few drips is one thing . With puddles something must be different. Are all tailpieces the same? Can you swap them. Are the flappers closing on that side? Like Geronimo mentioned 5 and 6 have in common the bottom edge of the tail pieces points right at them. I have seen water dance up hill before with help of harmonic vibrations. Even as I watched it I couldn't believe it.

Just for conversation when an exhaust has a water leak it will, depending on how bad, promptly develop a miss at idle. If you let it go on its own it will drop the cylinder then another. If you advance the throttle to about 2500 it will clear it self out and run smooth again as if it was flooded with fuel.

If after you have checked everything you can check you could ramp it, put a load on it, build some temp, and see if it will idle with out developing a miss. One guy did mention his problem went away after it got warmed up. I personally like to know everything is perfect but, I would ramp it before I disassembled anything further than you have. If it will idle indefinitely once warmed idling in gear on the trailer take it for a ride.

[Tony]

Did a compression test tonight for chits and giggles, 195 on all 8. looking back at the dry joint I didnt use a lot of silicone, basically enough to hold the gaskets in place. At this point Im guessing the culprit is less than a 100% seal at the dry joint, condensation with hose water, or a combination of the two. Im gonna put it back together with a liberal amount of silicone on both sides of the gasket and take it to the ramp.

[FULL FORCE]

Did a compression test tonight for chits and giggles, 195 on all 8. looking back at the dry joint I didnt use a lot of silicone, basically enough to hold the gaskets in place. At this point Im guessing the culprit is less than a 100% seal at the dry joint, condensation with hose water, or a combination of the two. Im gonna put it back together with a liberal amount of silicone on both sides of the gasket and take it to the ramp.

Hope all goes OK so you can finally use the boat!

[erierunnin]

Hope all goes OK so you can finally use the boat!

Same, good luck Tony, let's see her this weekend

[Ratickle]

Did a compression test tonight for chits and giggles, 195 on all 8. looking back at the dry joint I didnt use a lot of silicone, basically enough to hold the gaskets in place. At this point Im guessing the culprit is less than a 100% seal at the dry joint, condensation with hose water, or a combination of the two. Im gonna put it back together with a liberal amount of silicone on both sides of the gasket and take it to the ramp.

Take a spotter, leave the hatch off, good luck.

[Geronimo36]

Good luck with everything!!!

One last thing. I've found on the Stainless Marine's it's critical to make sure both mating surfaces are flat before tighening the v-clamp. If the end of the pipe is too high or too low it wont seal properly, no matter how much you tighten the v-clamp. That is one of my only complaints about the SM system.

When putting the pipes on for the first time I like to mock it up without the gasket and verify the flange on the pipe is level with the flange on the manifold. Again, if they're not flat you're going to have a hard time getting them to seal properly from what I've experienced, especially if you're running full length pipes thru the transom. On boats where you're connecting the pipe to a rubber hose you'll have some extra play but before tighening the v-clamp make sure it's all plumb.

[ChiefApache]

Tony, good luck!!! Our fingers, toes and whatever else we can cross are crossed hoping for good news.

[Tony]

I thought I would breifly touch back on this for anyone who may happen to stumble across this thread while searching for solutions to a similar problem.

On the SM reversion issue: It appears that the culprit was a combination of condensation from cold well water and possibly less than a 100% seal at the riser manifold dry joint. I ran the boat in the water and later removed the risers and found condensation on the top half of the pipe in the elbow, everything else was dry.

The riser to manifold jumper hoses are slightly kinked which may or may not be why water isnt filling the top half of the jacket at the elbow.

[DAREDEVIL]

I thought I would breifly touch back on this for anyone who may happen to stumble across this thread while searching for solutions to a similar problem.

On the SM reversion issue: It appears that the culprit was a combination of condensation from cold well water and possibly less than a 100% seal at the riser manifold dry joint. I ran the boat in the water and later removed the risers and found condensation on the top half of the pipe in the elbow, everything else was dry.

The riser to manifold jumper hoses are slightly kinked which may or may not be why water isnt filling the top half of the jacket at the elbow.

The water press. should fill it either way kinked or not. unless u have it plumed wrong.
Do u have a picture ???
Call Brownie @ SM ,,,he is always helping where he can.
I never had a problem with SM .