Volvo AQ-225E overheated

[JohnB.]

Looking for a little advice on how to check for overheat damage to this powerplant in a 86' trophy.

This is the first time it has overheated to my knowledge....I haven't had it long but I know the previous owner. Everything was operating fine, got a mile or so away from the dock, noticed the temp gauge was pegging so brought the throttle down and turned off the key. engine compartment was full of smoke when I opened it up so manned the extingushers. lots of clicking and popping from the manifold/head area and paint on the Y pipe darkened.

After system cooled (at home) hooked up the water (directly to the raw water pump hose) and it fired right up....ran fine! Didn't notice any external leaks of any kind but that doesn't say much. Ran motor for around 15 min with no apparent problems other then the starboard side of the Y pipe getting noticeably warmer then the port.

Found the culprit....the S hose connection at the outdrive (275) hose connecter was off due to connecter failure (metal corrosion/fatigue).

I would appreciate any ideas on "after event" checks to perform to detect any secondary damage. After reading some of the posts I am aware of some of the checks but a brief list would be helpful to avoid missing something important.

Thanks, folks.

 

[captmello]

Re: Volvo AQ-225E overheated

I suppose a compression test, you'll need new hoses on your exhaust of course.

Post the compression numbers and go from there.

Salt or fresh water?

 

[Don S]

Re: Volvo AQ-225E overheated

First test.
Start it up with water connected to the engine and see what happens.

If it's bound up, or has a heavy knock, well.............. Game over. No testing needed. Time for dissassembly and evaluation at that point.

 

[JohnB.]

Re: Volvo AQ-225E overheated

After system cooled (at home) hooked up the water (directly to the raw water pump hose) and it fired right up....ran fine! Didn't notice any external leaks of any kind but that doesn't say much. Ran motor for around 15 min with no apparent problems other then the starboard side of the Y pipe getting noticeably warmer then the port.

Don,
The motor seemed to run and sound as it did before the event....leading me to think that I may have gotten off pretty easy, however I am not so nieve to think unscathed. I haven't had the opportunity to pull the plugs to look for water or do a compression check, but I figure in addition to that I need to pull the risers to start looking for a reason for the uneven cooling I mentioned. I'm thinking that in addition to changing the impeller and riser hoses that there must be some other check I'm not thinking of to check for some other possible damage I'm not thinking of that's better delt with sooner then later.

 

[Don S]

Re: Volvo AQ-225E overheated

The big thing is, you never said you restarted it and all sounded fine.

but I figure in addition to that I need to pull the risers to start looking for a reason for the uneven cooling I mentioned.

The uneven cooling was probably due to the air leaks around the corroded off hose connection. It had to be a small leak before it was a big leak and caused the big meltdown. Yes pull the risers, you probably need new exhaust hoses anyway. They have to be burned up inside.

 

[JohnB.]

Re: Volvo AQ-225E overheated

Don,
I noticed the difference in Y pipe temp (port versus starboard, just aft of the riser hoses) after I had the garden hose hoseclamped into the raw water pump intake hose (isolating the broken part) after it overheated. I had not, before this, had a reason to feel the tops of the Y pipe so I have no reference as to whether this variation is new or not. I had been noticing before this event (and attempting to clean) some sediment from the manifolds. Poking at the buildup with wire to break it loose and flushing through the rear drainplugs. There could be quite a bit in there. I was thinking some may have flowed up the risers and plugged some openings. I've heard mention that it's a good idea to remove these parts (risers and manifolds) periodically, soak in some sort of acid mixture and "rodding" the openings for longer life. I know nothing about this procedure. If someone out there does I am all ears (eyes).
In short with this thread, I guess what I'm asking those that know..... if I find no water in the cylinders (cracked manifolds), detect no water in the oil (head gasket), detect no problem with compression checks (gasket, warped head, burnt valves), replace the raw water impeller-corroded water connector-riser hoses-riser gaskets, I may have gotten off lucky and there's no harm/no foul? Is this common.....or maybe uncommon but not unheard of? What else might I be on the lookout for?

 

[captmello]

Re: Volvo AQ-225E overheated

Again, is this a salt water boat?

If the fitting on the drive has corroded completely through, you can count on more corrosion elsewhere.

It sounds like you've been doing your best to keep the mani's cleaned out, but that type of debris can clog the risers. Can you post photos of the mating surfaces between the mani's and riser. I don't think you can clean out with acid.

If your running with the old rubber hoses on the risers, that could cause restriction and overheating of the Y pipe.

Do the compression check. The numbers will be very helpful and factual, not just speculation.

 

[JohnB.]

Re: Volvo AQ-225E overheated

Sorry, Yes it is a saltwater boat. Parts should be here in a couple more days. I will be able to change out the exhaust rubber then. In the mean time I will get the compression check done and post.
Thanks much.

 

[captmello]

Re: Volvo AQ-225E overheated

One thing that is almost certain, you melted the exhaust flappers. The question is where did they end up and are they blocking the exhaust?

I don't think you have flappers in that Model. Been wrong before though.

 

[Don S]

Re: Volvo AQ-225E overheated

 

[JohnB.]

Re: Volvo AQ-225E overheated

Just to keep anyone interested informed:
Was able to run the motor again last weekend...no trouble starting or running and sounded fine. warmed it up a little and turned it off. let the water run a little longer to force water through the manifolds. Checked the oil for water and found none. pulled the plugs and found no water on them. wanted to check these two items before letting is set a week until I could get back to it. So far looks like I must have been living right that day. Parts showed up tonight from North Carolina....should be able to get to it this weekend.....was able to get a compression gauge from Auto Zone for nothing....you pay up front and get your money back on return. Nice arrangement they have. Should be able to get those numbers on here soon after that. Thanks to all that have chimed in.