updated:AQ125A overheating

[JAL51974]

I was in the process of replacing the points+condenser with a Pertronix electronic ignition,started it up and the engine started overheating after 15 min. Conditions are: was running at high idle speed on muffs (tach not working so don't know exactly what rpms but it was sounding like high idle; was in middle of adjusting carb (soninlaw had "adjusted" it prior weekend! while starting tuneup process); watched temp gauge, went up to 200 deg. & shut it down. After shutdown there was steam coming from the bellows connected to the manifold, engine block definitely hot to touch, heat exchanger was too hot also.<br /><br />I had already inspected impeller pump and found the impeller to be intact, not beat up, but could not move it by hand either way is that normal? Left it in and just installed new gaskets after lubeing it.<br /><br />I plan to test the antifreeze & perhaps replace it if needed and inspect the impeller again. I am thinking it could be the thermostat too, don't know the age on it.<br /><br />Any other ideas of cause and diagnostic steps?<br />Did I do any damage, and if so what should I look for?<br />Thanks for the help.<br /><br />Joe

 

[Don S]

Re: AQ125A overheating

Re: AQ125A overheating

Did you have water hooked to the outdrive, and the secondary pickup blocked off, and have the water turned on full?

 

[JAL51974]

Re: AQ125A overheating

Re: AQ125A overheating

Water was hooked up on the muffs but the water was only turned on partway...had my buddy set it up. Secondary pickup...the small hole on bottom of the leg? how do you block it off?<br /><br />I think I screwed up...

 

[Don S]

Re: AQ125A overheating

Re: AQ125A overheating

the small hole on bottom of the leg? how do you block it off?

I have a tapered end off of a tube of sealer. (5200, Silicone, Lifecaulk, any of them) Used a piece of electrical wire to hold it on the muffs so I don't loose the end or leave it stuck in the drive.<br /><br />PS: It doesn't take near as much water to lubricate the impeller to keep it from burning up as it does to cool the engine.

 

[JAL51974]

Re: AQ125A overheating

Re: AQ125A overheating

thanks Don for that tip I will try it.<br /><br />so you think the lack of raw water caused the problem then? what about the steam, should I be concerned I burned something up? definitely was not a rubber or anything else burned smell.<br /><br />any tips on pulling the old impeller off??

 

[Don S]

Re: AQ125A overheating

Re: AQ125A overheating

Here's some hints.<br />For an operators manual go to this link and you can download one.<br /> http://www.volvo.com/volvopenta/global/en-gb/marineengines/operators_manual/operators_manual.htm <br /><br />For repairs, you really need a service manual, you need manual number 7739856. You can find a dealer locater at the above link. It's cheaper than the impeller, and has lots of uses.<br /><br />For your impeller, just use a couple of screwdrivers and pry out the old one. Be careful and don't damage the housing. Twist the new one in with dishwashing liquid on it as a lube (makes it a lot easier to install).<br />Then install new gasket on the cover plate and you are set.

 

[mcleaves]

Re: AQ125A overheating

Re: AQ125A overheating

Listen to Don on the overheat troubleshooting. He can find the damndest issues One more queston though. Were you getting water out the exhaust?<br /><br />As an FYI on the Pertronix on that engine. You will likely have to pull the distributer and rotate it a bit to get some headroom for ajustment after it's installed. <br /><br />M

 

[JAL51974]

Re: AQ125A overheating

Re: AQ125A overheating

Thanks don I will get that manual, the seloc one just isn't complete enough.<br /><br />I will replace the impeller tomorrow and let you know the result.<br /><br />mcleaves- did get water out the exhaust, just not much.<br />Joe

 

[Bsturkie]

Re: AQ125A overheating

Re: AQ125A overheating

Joe, I would clean your heat exchanger while you are changing the impeller. I cleaned mine (AQ125B) because it was very gunked up and had fragments of a old impeller stuck in the heat sinks. It dropped my temp by atleast 5 degrees. <br /><br />Good luck.

 

[JAL51974]

Re: AQ125A overheating

Re: AQ125A overheating

How difficult is that heat exchanger to dissassemble and clean out? I was thinking about tackling it too. the maintenance done prior to my purchasing it last year was questionable at best as I am discovering!

 

[JAL51974]

Re: AQ125A overheating

Re: AQ125A overheating

pulled the impeller out and it seemed pretty brittle but all parts were intact. the cover gasket had not installed correctly and a piece of it was inside the housing sort of impeding the impeller. weird things happen.<br /><br />thanks for all the advice.<br />Joe

 

[Mischief Managed]

Re: AQ125A overheating

Re: AQ125A overheating

Originally posted by JOE LOIZZO:<br /> How difficult is that heat exchanger to dissassemble and clean out? I was thinking about tackling it too. the maintenance done prior to my purchasing it last year was questionable at best as I am discovering!

You can take it off and chemically clean it without disassembly using Muriatic acid. I have posted about in the past right here.

 

[JAL51974]

Re: AQ125A overheating

Re: AQ125A overheating

update:<br />changed impeller and put in fresh antifreeze. still the engine is overheating and Had to shut down. a white steam/smoke was coming from the bellows connecting the manifold to the exhaust. not a burning smell though. full water turned on muffs plus the additional uptake hole was blocked off so it was getting plenty of water into the heat exchanger. <br /><br />should I assume it is the insert in the heat exchanger clogged up...don't know when it was serviced if ever. old impeller was needing to be replaced with one fin ripped but there was no pieces missing.<br /><br />what do I check next?<br /><br />Joe

 

[JAL51974]

Re: AQ125A overheating

Re: AQ125A overheating

I forgot to add that while running the engine there was very little to no water coming out the exhaust.

 

[Don S]

Re: AQ125A overheating

Re: AQ125A overheating

You may need to pull the exhast manifold and see if it's plugged up with rust in the water passages. You may be getting water into the manifold and heat exchanger, but unless it goes out there is no circulation. Thus an overheat.

 

[JAL51974]

Re: AQ125A overheating

Re: AQ125A overheating

what do I tackle first? heat exchanger insert or check the exhaust manifold for rust in the passages?

 

[Don S]

Re: AQ125A overheating

Re: AQ125A overheating

If you aren't getting a lot of water out the back, check the manifold first. If you have good water flow, check the heat exchanger.

 

[JAL51974]

Re: AQ125A overheating

Re: AQ125A overheating

Well here is where I got stuck. I decided to examine the insert in the heat exchanger first since upon looking down the exchanger mouth I can see all sorts of gunk in the top of the insert.<br /><br />I can remove the fresh water tank and all the bolts on the raw water tank except for the two bolts connected to the copper pipe mounting- see picture. Photobucket<br /><br />when I turn these they feel stripped in the plastic housing. Won't loosen or tighten either way. any suggestions for removing them, the housing won't budge without removing them and the whole heat exchanger cannot come off without it.<br /><br />Joe

 

[JAL51974]

Re: AQ125A overheating

Re: AQ125A overheating

Bsturkie- just got around to looking at your project boat.<br />nice restoration project on your Capri.<br /><br />Does your throttle have any problems putting it into throttle only? Mine doesn't seem to work that way, can only start in Neutral, no throttle only to goose the gas if needed.<br /><br />joe

 

[Don S]

Re: AQ125A overheating

Re: AQ125A overheating

You need a new plastic strainer housing for one thing. It has threaded inserts molded into the plastic that may have spun in the plastic. <br />If that is the case, cutting it off is about the only option. <br />I sure hope you have a Volvo manual on that system since you are obviously taking it apart.<br />Getting all the parts back it the proper order can be a real chore at times, and if it's not right, it will leak. You also do NOT reuse any gaskets or orings or other seal rings in the cooling system. They get NEW ones.