port side exhaust elbow over heating.

[flashback]

1995 searay 220 5.7 alpha1 gen 2 with sei drive..
I'm hoping you folks can help me, like the thread title says the port side elbow gets very hot soon after cranking the engine. The riser and the rest of the exhaust system is still cool to touch but that one elbow will almost burn you. The impeller is new, I pulled the input hose at the thermostat and its pumping plenty of water. I'm lost, I have never had to deal with overheating other than a bad impeller on my other boat.

 

[Lou C]

You probably have either a clogged water passage in that elbow or low water flow to that side of the exhaust system. Start at the thermostat housing and see if flow to both sides is equal, if not then you have to remove the stat housing and clean it out, they do get clogged with rust, crud or bad impeller bits. If not that then you will have to remove the elbow on that side.

 

[flashback]

Thanks Lou, I was planning to replace the tstat anyway so I'll start there, I may have my terminology wrong as what I meant was the elbow that's after the riser elbow, I haven't taken it off yet but from the outside it doesn't look like it would have any double wall passages.

 

[Scott06]

Thanks Lou, I was planning to replace the tstat anyway so I'll start there, I may have my terminology wrong as what I meant was the elbow that's after the riser elbow, I haven't taken it off yet but from the outside it doesn't look like it would have any double wall passages.

No the down elbow is single wall, water and exhaust mix at the riser elbow. Take it off you may have clogging at the outlet of the riser elbow and perhaps the water isnt cooling all of it. Does that manifold and elbow stay cool otherwise ?

 

[flashback]

No the down elbow is single wall, water and exhaust mix at the riser elbow. Take it off you may have clogging at the outlet of the riser elbow and perhaps the water isnt cooling all of it. Does that manifold and elbow stay cool otherwise ?

Yes, the manifold and riser were cool only the down elbow was hot after 5 minutes of fast idle, the engine was not warmed up. Something must be blocked. Would a flapper cause this?

 

[Scott06]

Yes, the manifold and riser were cool only the down elbow was hot after 5 minutes of fast idle, the engine was not warmed up. Something must be blocked. Would a flapper cause this?

I think the flappers are below this in the top of the wye pipe.

Does your thermostat housing have the T with plastic balls/poppet valves ? these fan pass too much water to one side or the other if hung up .

 

[flashback]

That's beyond my knowledge about all I can say is it has 6 hoses connected to it. I can get a pic of it and post back. And thanks for the guidance.

 

[Bondo]

That's beyond my knowledge about all I can say is it has 6 hoses connected to it. I can get a pic of it and post back. And thanks for the guidance.

Ayuh,.... Was this problem in the water, or on the wagon,..??
If it was on the wagon, just not bein' dead level can cause such a thing,....

Is there one water hose goin' into the bottom of the manifold, 'n another goin' into the riser elbow,..??
If so, pull those hoses, one at a time, 'n check for flow,.....

 

[flashback]

Ayuh,.... Was this problem in the water, or on the wagon,..??
If it was on the wagon, just not bein' dead level can cause such a thing,....

Is there one water hose goin' into the bottom of the manifold, 'n another goin' into the riser elbow,..??
If so, pull those hoses, one at a time, 'n check for flow,.....

Yes there is a hose at the bottom where the drain plug is and and another one in the riser. The boat was on a lift but almost free. Probably had a bit of list but not much.

 

[Bondo]

Yes there is a hose at the bottom where the drain plug is and and another one in the riser. The boat was on a lift but almost free. Probably had a bit of list but not much.

Ayuh,..... It don't take much,.....

 

[flashback]

Thanks, I will pull the hoses to check.

 

[flashback]

And free the boat and check again, didn't know a bit of list could cause this. Would it still happen when running? Me and the battery are on the same side so I suppose that the boat is leaning to starboard most of the time.

 

[Bondo]

And free the boat and check again, didn't know a bit of list could cause this. Would it still happen when running? Me and the battery are on the same side so I suppose that the boat is leaning to starboard most of the time.

Ayuh,..... Water, seeks it's own level 'n flows downhill....

It coulda been dumpin' 99% of it's water to the low side,....

 

[flashback]

Now my curiosity is up, what are the poppets and balls that @Scott06 spoke of? Something tells me that I probably don't want them..LOL

 

[Scott06]

Now my curiosity is up, what are the poppets and balls that @Scott06 spoke of? Something tells me that I probably don't want them..LOL

You don’t have them on your set up. My 2004 has them basically it feeds water to risers and manifolds separately risers cold incoming water , manifolds only get hot water after thermostat opens. Works fine on mine

 

[flashback]

Ok, that probably prevents the scenario that Bondo was describing, maybe I do want them. I come from an MC1 in a 1980 CC which had log manifolds and honestly was not much trouble. This new to me boat is a learning experience.

 

[Scott06]

Ok, that probably prevents the scenario that Bondo was describing, maybe I do want them. I come from an MC1 in a 1980 CC which had log manifolds and honestly was not much trouble. This new to me boat is a learning experience.

No it doesn’t prevent that it is only to have warm exhaust manifolds theoretically preventing condensation during warm up

 

[flashback]

Finally had decent weather and was able to work on the boat today. I pulled the hoses from the riser and manifold and water flow seems good. So I put them back on and cranked it up to see if the elbow would heat up. I saw water coming out of the lower exhaust boot at the y pipe so pulled the riser and elbow as one unit. The lower boot has cracking and appears burnt. The flapper and it's axel are both bent and appeared jammed in the y pipe, I retrieved them intact.

 

[Bondo]

Finally had decent weather and was able to work on the boat today. I pulled the hoses from the riser and manifold and water flow seems good. So I put them back on and cranked it up to see if the elbow would heat up. I saw water coming out of the lower exhaust boot at the y pipe so pulled the riser and elbow as one unit. The lower boot has cracking and appears burnt. The flapper and it's axel are both bent and appeared jammed in the y pipe, I retrieved them intact.

Ayuh,.... Did it heat up,..??

At some point, it's been run without water,....
Yer gonna want a can of Quicksilver Power Tune to put a new bellows on the y-pipe,....

 

[dubs283]

Ayuh,.... Did it heat up,..??

At some point, it's been run without water,....
Yer gonna want a can of Quicksilver Power Tune to put a new bellows on the y-pipe,....

Yeah, what was temp? Riser hot again?

Replace boot for sure and flappers, they're toast. New gaskets in order for riser/elbow too. Better inspect other side as well