AQ125B (85 Bayliner 1950 Capri) Overheat

[hitest1024]

OK, I finally worked through my starter issues, and (painfully) my water contaminated gas issues, and it starts and runs perfectly now. For a minute or two, then it overheats (temp up to 200-220) and the cap blows coolant onto the engine block. It overheated in the driveway, after a minute or two idling as I tested the other fixes, but I thought it was because the earmuffs weren't hooked up . But then I got it on the lake and less than 5 minutes in, smoke from the engine compartment.

It's had a slow drip (possibly from the pump area) since I had the head rebuilt this spring. Is there anything else this could be besides the pump? Is there any way around this 1000 dollar pump that the dealer sells? I was laid off in june, and there's no way that's happening.

I searched the forum and found the overheating trouble shooting guide, but I'm not sure it applies..
Any advice welcome- thanks.

 

[captmello]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

do you have good water flowing at the strainer? Have you checked/replaced the thermostat?

 

[hitest1024]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

I'll check that today- I can put earmuffs on and maybe take out the thermostat (haven't located it yet...)

I only suspected the water pump first because of the drip from around the pump area- (remembering that every failing water pump I've had on a car has been preceded by that slow drip- just wondering if it works the same way on boats.)

Thanks- I'll post when I have checked the flow and the stat.

 

[sqbtr]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

The drip does mean impending failure, but, is probably not the reason for the overheat. Check what captmelllo suggested first.

The water pump is specific for that motor and is pricy, I have heard of rebuilders getting about $200 for an O/H. I'll see if I can find the info on rebuilders.

 

[hitest1024]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

OK, I hooked up the ear muffs and cranked the engine, but I'm getting no flow of water into the engine (though I didn't get it up to operating temperature...)
The water from the earmuffs was coming out the hole directly below it. From the engine compartment side, I unhooked the flexible black hose from what I assumed was the silver freshwater intake tube, and I did feel a slight amount of suction on the engine side, but it wasn't drawing water up...
This is the view of the hose I disconnected, from the engine compartment side:
http://www.flickr.com/photos/evanreese/6046692219/in/photostream

Does any of this point to a problem?? Or do I need to do a specific test?
Thanks again.

I didn't check the thermostat yet- not sure if I have to remove the whole reservoir, or if I can just take off the housing....

 

[bruceb58]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

This isn't your problem but make sure you plug the alternate inlet hole on your drive when you run on muffs. Its a small hole near the nose cone.

Have you replaced the rubber impeller in the raw water pump?
http://www.dougrussell.com/partscat...,1880,1881,1882,1866,1887,1870,1886,1875,1877

 

[captmello]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

you should plug the hole in the bottom of the outdrive when running on muffs. check the hose coming from the outdrive to the transom shield. It attaches right below the ujoint (upper) bellows. That hose connection on the outdrive is prone to corrosion. Loosen the clamp and pull off the hose to check it. In the mean time, you could run your hose directly to the hose you removed in your photo and see if you have water flowing through the strainer that way.
Have you checked the impeller??????

 

[hitest1024]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

Ok, with the engine running, I put a running garden hose into the black hose in the picture... Even when tightening the black hose with my hand to force water into the system, I got only a very tiny, barely nori able trickle at the strainer, and water was quickly forced back out by the pressure where I was holding it.

Does this indicate seawater pump?

Also- not sure how to plug the alternate intake, but when I hold my finger in it with the muffs on, shouldn't it bubble out where The hose is disconnected in the engine compartment?

Thanks yet again

 

[bruceb58]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

Captmello and I are going to ask the same question again!!!!!! Have you changed or inspected your raw water pump impeller?

Also- not sure how to plug the alternate intake, but when I hold my finger in it with the muffs on, shouldn't it bubble out where The hose is disconnected in the engine compartment?

Yes it should. When I had that drive a long time ago, I had a rubber cork that I shoved in there.

 

[hitest1024]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

You and captmello were of course correct!
I figured out what the impeller was, opened the seawater pump, and of course there wasnt much left of it (maybe 2 or 3 fins). I'll get another, but I'm wondering if I need to make sure the other pieces of fins arent clogging up the system?

A thousand thanks.

 

[bruceb58]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

Yes, you need to locate them.

 

[hitest1024]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

Ok- one final question (the answer isn't in the manual)- when I install the new impeller, which way do the fins tuck in? I have it so that the fins trail behind if the shaft spins clockwise. (in other words, the base of the fin hits 12 o'clock before the top of the fin)...
Thanks

 

[Mullin]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

That sounds right. It rotates clockwise so just spin the impeller clockwise by hand as you install it. If you do it wrong, new impellers are nice and flexible and will correct themselves just fine.

The bits and pieces of your old impeller should be trapped in the strainer basket in the top of the heat exchanger. Clean it out now and then again after you run the new impeller for a minute or two to flush out any old bits in the hoses.

I don't even bother with earmuffs on mine anymore, they are just to problematic. I just go with a garden hose clamped into the black hose. Just be sure to turn the water off when the motor is off because the impeller will act as a water stop when its not spinning.

The smoking you where getting was probably your exhaust bellows boot at the back left of the engine compartment, starting to catch on fire because it didn't have any water flowing through it. Watch your gauge more carefully to not go over 190 anymore, shut it down. Also be sure that you have water exiting the flapper on the outdrive right from startup to ensure you are getting freshwater to the exchanger and through the exhaust.

 

[hitest1024]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

Mullin was right that the exhaust hose was damaged.... Does anyone know for sure whether the exhaust manifold has to come off To change it for the aq125b/270 setup? Ive seen different opinions on the biards here. Also, any hints on the cheapest source welcome- found it at vp for 85, but hoping for cheaper...

Otherwise though I'm back in the water and very happy- thanks to all

 

[sqbtr]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

Yes it has to come off, and, you can check the #4 exhaust port at the same time.

 

[Mullin]

Re: AQ125B (85 Bayliner 1950 Capri) Overheat

I have the aq 125a engine, the boot just has a clamp on the top and on bottom both. I managed to get a new one on without removing the manifold, it was a pain but I got it.

I cut off the old boot and then pushed and pulled to get one lip through the tiny gap and down onto the exhaust pipe. Then I used two pliers for a better grip and pulled the rest of the boot onto the pipe. Then pulled it up to the manifold and.clamped it.

It wasn't exactly easy, I'm a strong 200 pounder, but took like 15-20 minutes of wrestling.

I couldn't find a cheaper one either.