Overheating

[KWKloeber]

[edited to add link]
Is the mixing wye cracked and leaking or is the riser shot?

If it was "just" a cracked inlet, IIWMB I'd try ANY plan but replace the riser away from home.
Fiberglass muffler wrap, rubber& hose clamps, silicone rescue tape, bubblegum, all of the above, ANYthing but get into that can of worms where you are. 

But not having eyes on maybe not possible, and ya gotta do what ya gotta do.   

Here's Paul's posts on his cracked wye that turned into a riser replacement - note that it's on an XP.
http://c34.org/bbs/index.php/topic,9026.0.html

Or limp home and see if you can maybe do the better plan, water-cooled riser (that, yes, is possible on the C34) as Biil installed.
http://www.c34.org/wiki/index.php?title=C34_Exhaust_with_Water_Cooled_Riser

[Brad Young]

There is a hole in the riser. About the size of a silver dollar. This is at the elbow just above the "Y" nipple It is rusted through. Working on pulling it it out.
Will get a guy here In Mexico to fabricate a new one.
We do not plan on taking DarBay back to the states for at least 2 or 3 years. So every has to be fixed here.

[Ekutney]

I replaced my Exhaust Riser 2 years ago & it is quite a job.  Good idea soaking the manifold bolts with PB, give them time.  In my case when I removed the old one it just fell apart, almost like the insulation was holding it together.  I was in the US so I ordered a SS one from CD. 

While reading through the forum to gather info to replace the riser I found a few people that talked about having a unit fabricated some used SS but others used Black Pipe (obviously will not last as long as SS).  Also keep in mind the hump hose if it did not have one.

[mark_53]

I have an old one sitting in my garage.  It's the old SS original.  I replaced it last year as a proactive step to avoid a remote problem.  Let me know if you want me to ship it out for the cost of shipping.  The heat shield is damaged but the riser still seems good.

[Stu Jackson]

I replaced my Exhaust Riser 2 years ago & it is quite a job.  Good idea soaking the manifold bolts with PB, give them time.  In my case when I removed the old one it just fell apart, almost like the insulation was holding it together.  I was in the US so I ordered a SS one from CD.  >>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>

The last Mainsheet Tech Note on exhaust riser replacement was Feb 2016, Muffler & Exhaust Riser Replacement
http://c34.org/muffler-exhaust-riser-replacement-2015/

[Ron Hill]

Brad : When you install your new riser make sure that you do NOT use the original stiff wire reinforced hose from the anti-siphon to the nipple on the riser.  Use softer nylon reinforced hose instead!!

A thought

[KWKloeber]

Brad

You didn't say what locally you were going to have them fabricate. I've always planned if/when I need to replace mine -- if I don't use the water-cooled riser, I would fab one using schedule 80 pipe rather than sch 40 so that it lasts 2x as long.

[Roland Gendreau]

Replaced my riser last year, and bought the unit from CY.   CD would not sell me a riser unless I also bought their insulation, which was wildly overpriced.   CY included all the insulation needed at no extra charge.   Replaced the hump hose at the same time.

[senorquill]

We are sailing in Mexico.. we are currently having an engine over temp issue.
1) if we keep the rpm below 1800 it seems to run ok.
2)over 1800 rpm the temp slowly creeps up to at least 200, then I put her in neutral and rev engine  to cool her down.
3) when she is running hot, there is no steam in the engine compartment.
4) there is some gray soot (not black diesel) in the compartment below the head sink.

What I have done
1) pulled raw water pump look good, checked water flow to the riser and exchanger flow looks
Normal
2) pulled heat exchanger it was clean. We recently had it boiled at a radiator shop (2017)
Questions
1) is there a way to check flow on the freshwater (antifreeze) side. When looking at the antifreeze with the cap off there does not seem to be much flow
2) is there a way to see if there is a blockage riser?

Any thoughts would be greatly appreciated

I'm bringing the thread back up since this exact thing is happening to me right now. I've been out for 3 days, still got to get home. Of note, I used all my hot water, and I just ran the engine for 30 mins in a pass and it over heated gain, when I dropped hook their was no hot water still. Is this an air lock? The HX was warm, not really hot. To burp do I just loosen the deal in the photo and take her up to 3000rpm? Before this trip I changed oil, new fuel filters, topped up coolant, cleaned raw water intake even below water.

[Ron Hill]

MQ : No that is not the "burp" hose.  However, you can run the engine and see if some air comes out of that butterfly valve when you open it.

To "burp the engine" you need to take the hose off of the thermostat and make sure that it is full of fluid.  Look in the critical updates and WiKi for the detailed procedure to burp the engine. 

Then you really need to add a coolant recovery system (easily done WiKi)

A few thoughts

[senorquill]

We are sailing in Mexico.. we are currently having an engine over temp issue.
1) if we keep the rpm below 1800 it seems to run ok.
2)over 1800 rpm the temp slowly creeps up to at least 200, then I put her in neutral and rev engine  to cool her down.
3) when she is running hot, there is no steam in the engine compartment.
4) there is some gray soot (not black diesel) in the compartment below the head sink.

What I have done
1) pulled raw water pump look good, checked water flow to the riser and exchanger flow looks
Normal
2) pulled heat exchanger it was clean. We recently had it boiled at a radiator shop (2017)
Questions
1) is there a way to check flow on the freshwater (antifreeze) side. When looking at the antifreeze with the cap off there does not seem to be much flow
2) is there a way to see if there is a blockage riser?

Any thoughts would be greatly appreciated

I'm bringing the thread back up since this exact thing is happening to me right now. I've been out for 3 days, still got to get home. Of note, I used all my hot water, and I just ran the engine for 30 mins in a pass and it over heated gain, when I dropped hook their was no hot water still. Is this an air lock? The HX was warm, not really hot. To burp do I just loosen the deal in the photo and take her up to 3000rpm? Before this trip I changed oil, new fuel filters, topped up coolant, cleaned raw water intake even below water.

Universal M25xp w/ 3" heat exchanger. I put a brand new HX on last year.

[senorquill]

MQ : No that is not the "burp" hose.  However, you can run the engine and see if some air comes out of that butterfly valve when you open it.

To "burp the engine" you need to take the hose off of the thermostat and make sure that it is full of fluid.  Look in the critical updates and WiKi for the detailed procedure to burp the engine. 

Then you really need to add a coolant recovery system (easily done WiKi)

A few thoughts

Okay. Do you think it is an airlock, before I mess with that? I have to coolant recovery just need to put it back on.

[Ron Hill]

 MQ : Yes, there is a airlock in the engine to water heater hose back to engine hose!!!

A thought

[scgunner]

MQ,

The best way I've found to eliminate air from the coolant system (airlock) is to remove the radiator cap, start the motor, then gun it a few times up to around 2000rpm. That should blow any air out the cap opening, it will spit up a bit so you might want to place some rags around the opening.

You'll know it's successful if afterwards there's a significant drop in the coolant level in the coolant tank. Then top it up replace the cap and you should be good to go.

[KWKloeber]

If you're not getting ANY coolant movement (to neither the Hx nor the WH) I'd think there's two possibilities- (a) an airlock in the pump itself (this happened to a friend with an XP after replacing the coolant pump and meticulously filling the system) or (b) an airlock in both circuits (to/from Hx and to/from WH).

There was a recent thread about an airlock cleared from the return hose from the Hx to the coolant pump.

If after purging all air you still overheat check the TStat to ensure it opens 160F, or it's cheap insurance to just replace it with your spare if it's got many years on it. Or remove it to temporarily run w/o a TStat until you can replace it.

I find that most times I can get all air out by bleeding at the pressure cap after she's up to temp and the TStat opens. We have a particularly difficult inherent airlock issue because the C30 mk-I's WH is high in the cockpit locker and a long run from the engine so air tends to settle in there, but the pressure cap method seems to work 9 out of 10.

Here's the coolant flow directions:
https://groups.io/g/Catalina30/wiki/9626