Burning Holes in 4" exhaust hoses

[rcknecht]

On the starboard side of my port engine (7.4 MPI FWC "v" drive). I have burned through three 4" manifold hoses. The engine is not over-heating. It is always the same side. This did not happen last year, and it started when I began using the boat this year.

Prior to the have the hose problem. I replaced my Verilift muffler and in manifold zincs (I have a HiTek SS one piece exhaust).

Since the problem. I checked the transmission cooler, and engine HE. I replaced the RW host to the Exhasust Manifold. I had my strainer rebuilt. I cleaned and painted the bottom. The RW pump is only 2 years old and the flow looks stong when idling.

This problem happens after running the boat on plane for between 2 to three miles... It is frustrating... PLEASE HELP me... thanks

 

[Saverio]

I think it might be be your pump. Mine is great at idle looks like the other motor but when i go out my port motor runs hotter. i took the pump apart over weekend and saw I had three blades that were ripped and ready to fall off. be carefull with CO gas

 

[rcknecht]

I plan on replacing the water pump next... What about the Oil Cooler... It is hard to get to and I have have neglected it... Could the engin oil cooler be a casuing this problem...

 

[Saverio]

only times they have problems is when the impeller brakes and parts of it gets stuck in. when u remove the impeller make sure u have all the blades. the cooler is just a tube with the oil line running through it. no moving parts nothing really to maintain

 

[Air O'Nautical]

Your engines not overheating but, your manifolds are.
Got to be a raw water flow problem because, those manifolds are raw water cooled.
I agree to change the raw water impeller first but, if it looks OK you may want to look for a blockage starting at the through hull and going through the whole system to ensure its clear.
The oil cooler and trans cooler could be blocked by sealife and its worth checking those..


I know those exhaust hoses aren't cheap!



Sorry, if I'm just stating the obvious that your manifold(s) isn't flowing enough cooling water through at least part of it and its getting hot.


Happy hunting,

 

[rcknecht]

The Transcooler is good... I have neglected the oil coolers mainly because they are PITA to get to... The hose clamps on both of oil coold have rusted off... My plan is to replace the RW pump and give my oil cooler an eninma...

 

[Bucit]

Ney Rod, I had an issue with one of my Hi-Tek manifolds over the weekend. Port motor as well. Hopefully your issue is small and inexpensive.

 

[rcknecht]

Ney Rod, I had an issue with one of my Hi-Tek manifolds over the weekend. Port motor as well. Hopefully your issue is small and inexpensive.

I cut one apart this spring an reinstalled one that had a crack flange (it was repaired by a machine shop). I had to cut it off with a sawsall because I could not turn the screws. I reinstalled screws with 7/16" heads to get it off easier next time... The one that failed had a cracked flange. By the thinning of the exhaust walls, I estimate two years left on the manifolds before I will have to replace them all. That gives them a life span of six years, which is less than I had hoped for...

 

[KC_Sundancer]

Pull the upper hoses off the top of your thermostat. There is a pin with two balls and springs. Check that they move freely as the balls sometimes get stuck not allowing cooling water to flow out one side or the other. Had this happen with with our Pachanga.

 

[rcknecht]

Pull the upper hoses off the top of your thermostat. There is a pin with two balls and springs. Check that they move freely as the balls sometimes get stuck not allowing cooling water to flow out one side or the other. Had this happen with with our Pachanga.

My boat is Fresh Water cooled... I don't think the thermostat can cause the problem... If my boat was RWC the thermostat would be the first place I would look... Thanks...

The hoses are about $30-$50 a each...

 

[Jimmy Buoy]

I had this issue when I first got my boat. Ended up being blockages within the exhaust manifolds were restricting water flow enough that there wouldn't be enough of a "spray" where the elbow met the rubber exhaust hose to keep it cool. Under higher RPM's the hot exhaust burned a hole through the top of the hose. There was enough water flow diverted to the other manifold that didn't seem as plugged that the engines never did show signs of overheating whatsoever.

Good Luck!

 

[rcknecht]

I am starting to think the some pieces of my zinc has broken off and is clogging my manifold... The Hi-Tek manifold is a one piece header. I replaced the large zinc this spring... I will start there...

 

[Bucit]

I cut one apart this spring an reinstalled one that had a crack flange (it was repaired by a machine shop). I had to cut it off with a sawsall because I could not turn the screws. I reinstalled screws with 7/16" heads to get it off easier next time... The one that failed had a cracked flange. By the thinning of the exhaust walls, I estimate two years left on the manifolds before I will have to replace them all. That gives them a life span of six years, which is less than I had hoped for...

Mine did fail and now I'm a little weary of the other 3 that are on there.

 

[rondds]

Rod
The elbow portion of the SS mainfolds (I know they're one piece, but the top part)...how hot is that? Did you shoot temp readings there with a IR temp gun? And shoot readings at various other points (Therm housing, heat exchanger, etc.)

 

[Bucit]

I am starting to think the some pieces of my zinc has broken off and is clogging my manifold... The Hi-Tek manifold is a one piece header. I replaced the large zinc this spring... I will start there...

Even more ironic. I pulled the zinc of the failed manifold and it was rusty and white (but almost the whole thing was left). The zinc actually broke off the cap and I had to pull it out of the manifold

 

[rcknecht]

Rod
The elbow portion of the SS mainfolds (I know they're one piece, but the top part)...how hot is that? Did you shoot temp readings there with a IR temp gun? And shoot readings at various other points (Therm housing, heat exchanger, etc.)

It is hot but the design would insolate with a air almost as good as if there was water flowing through it... I don't have an IR gun, its on my list... I did replace my faulty horn...

 

[rcknecht]

Mine did fail and now I'm a little weary of the other 3 that are on there.

How did it fail? Is it leaking exhaust gas or water? I have weeping of water coming out of mine, which has dripped down on to my cool fuel HE, which is why my clamps rust off...

 

[rondds]

Can I make a suggestion?

 

[mistercomputerman]

Can I second that suggestion?

 

[rcknecht]

Can I make a suggestion?

This is my plan, but I was hoping to get one more year. Where is the best place to buy OEM exhausts?