Help with 270 and AQ 125

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skagitcom

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Aug 11, 2010
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I have a Bayliner Capri with the Volvo Penta AQ 125 and 270 outdrive.
I just bought it after it had been sitting for over 7 years.
I got it running after draining the gas, charging the old Die Hard, and installing new plugs. I .sed mouse ears with a water hose. No water comes out of the exhaust. I opened the raw water cap above the heat exchanger and saw no water. I put water into the exchanger and still nothing comes out of the exhaust. I then pulled the cover for the raw water pump that drives off the timing belt. The water I put into the exchanger came out.
Is ther another water pump in the outdrive leg?
Sorry, I have no manual.

TNX Tom
 

captmello

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Re: Help with 270 and AQ 125

did you change the rubber impeller in the water pump? It must be bad after sitting that long.

No there is not a pump in the outdrive.

Before running the boat, I would drain the outdrive and refill with 30w motor oil. Examine the old oil, looking for water.

If you study the cooling system, you can see the raw water exits the heat exchanger and goes up into the exhaust manifold, so pouring water in may not make it through the exhaust and out the drive.

Also, while the cover is off of the impeller housing, turn the engine over to make sure the shaft is turning the impeller. There is another rubber part behind the housing that connects and turns the shaft.

Good luck, let us know how it goes. And if you have more questions:)

BTW, Welcome to Iboats. There's lots of great help here.!!
 

skagitcom

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Re: Help with 270 and AQ 125

Thanks for the reply.
I have learned a lot since my last post. In fact I could qualify as a AQ125/270 expert;);)

The reality is, I found that I can't get water up to the raw water pump with mouse ears. After finding the hole in the bottom of the 270 leg and plugging it, water still will not pull up to the raw pump when the engine is running.
I finally took the boat to a local lake and backed it in to test. The raw water pump probably pumped OK before I rebuilt it, but now it is a brute. I found that the Raw water tank cap leaked very bad. Water sprayed everywhere. I temporarily fixed it by gently bending the cap with a set of water pump plyers. There was a antifreeze leak, so I ended up having to replace the engine water pump. My Volvo Penta parts shop said that is rare to have one go bad. Sitting for 7 years must have dried out the seals. The new pump is not the same (re-engineered), and was a B@#$%ch to make work. After many hours reworking rubber seals and putting O rings where square round rubber seals go, I finally got the engine water leaks fixed. Then when I took it to the lake for a test, the cap for the raw water leaked again and I found more small raw water leaks. One at both ends of the raw pump output tube.

I have gone through all the seals again and will test it tomorrow.

The good is... The engine runs very well and starts with just a few pumps of the throttle. It idles at 1000 RPM with a temp of 180 and oil pressure at 40 to 50 when hot. All the guages work as new.

I bought a pump to change the engine oil and as you recomended I have checked the leg for water (none) and will change the oil before taking the boat for a run.

More later
Tom
 

skagitcom

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Re: Help with 270 and AQ 125

UPDATE!!

After testing again at the lake and finding more raw water leaks, I bought all new seals for all the raw water fittings including the double square seals with the nylon ring for the heat exchanger neck.
I also bought a new raw water cap ($56.00)
I took the boat out to test it with the whole family (6 of us). It ran very well but I noticed after some time at 3500 RPM on plane, it crept up to over 190 to 200 or more (hard to tell). When I came back off plane and cruised at 2000 to 2500 it came back to 180. I tried installing the new raw water cap but it leaked badly (1st clue).
I got home and stuck the leg in my plastic water tank and ran it to check for leaks, and found that the raw water pump blew out the new seal I had installed (clue 2).
There is a lot of pressure on the outlet side of the raw water pump and i am wondering if there is a restiction somewhere. With the motor stopped there is pressure built up on the outlet of the pump. If I break a connection it will blow the pressure till gone.
Question.... Is what I have explained normal?
how can I check the flow through the exhaust manifold to the leg. I can't find any information on how that system works.

I found a rebuilt pump in Florida (new bushings, seal, impeller, etc. for 145.00. I may try another seal on mine before buying it after talking more with my local Volvo Penta folks.
Thanks again.
Tom
 
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Fun Times

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Re: Help with 270 and AQ 125

Your heat exchanger needs antifreeze as well, Not just water.;)

I recommend getting a service manual for your engine, It will help you out a lot with this engine.

When you do get this engine running correctly by the book, You'll have a really good engine on your hands.:)

Good luck with it, And enjoy your new boat.:)
 

cr2k

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Re: Help with 270 and AQ 125

Probably some of the old impeller (our a long ago one) pieces are blocking flow somewhere downstream in the system.

Not unusual to have to replace that cap either.
 

captmello

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Re: Help with 270 and AQ 125

you shouldn't have pressure on the raw water side of the cooling system. What did the old impeller look like when you removed it?

I have heard other complaints about the caps leaking as well. Common, like cr2k said.

Any water passing through the heat exchanger, should flow right through and out the exhaust with no restriction. Could the boat have been in salt water in the past?

The overheating your experiencing is also common and is usually the intake fitting on the outdrive just bellow the ujoint bellows. Remove the rubber intake hose and inspect the fitting, Looks like this.



Let us know what you find.:)
 

occarvers

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Re: Help with 270 and AQ 125

I have the same setup had to replace the hole assembly on top of the heat exchanger. If the cap gets tightened to much the plastic will crack. As with any VP part it's pricey to replace. Also after running in lake water you should check the strainer inside the heat exchanger. They can suck up seaweed. Could be part of your heat problem. I have gone down the same road, replaced all seals in the coolant system. My temp max is 180. May want to verify what your t stat is opening at. Test in a pan of water on the stove with a thermometer. I agree with Boat Tech it is a great little motor. Runs strong and is very fuel efficient.
 

skagitcom

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Re: Help with 270 and AQ 125

All of your suggestions are very noteworthy.

The old impeller looked very good. The only reason I replaced it was because it had rubbed off some rubber onto the sides of the pump. It was still after sitting for years, very flexible. The seller told me it had been changed just before storage.

The black plastic neck on top has been replaced.

There are no leaks on the suction side. There is so much pressure I had to put another shim under the rubber of the raw water cap.. When I was first trying to get water up the leg with mouse ears, I checked by putting water down the suction tube. It flowed right back out the leg with no leaks anywhere on the way.

I looked at a parts breakdown of the heat exchanger last night and discovered the strainer. I don't have one.

When replacing the neck seals I found a broken piece of a old neck sitting on top of the heat exchanger insert.

I believe the blockage is after the heat exchanger. When I removed the outlet tube there was pressure there also. When I remove the Raw water cap, there is always water sitting right to the top and it doesn't flow out the tube to the exhaust manifold. Only under pressure does water flow.

I hear you that there shouldn't be pressure there. Looks like what you are all saying is, that I should remove the exhaust manifold and see if maybe it is plugged up.

To boat tech. Is the service manual I see for sale on this site a good one? Will it show me the whole system? I borrowed a copy of a Volvo service manual, and found that my imagination worked better.

Any more suggestions are very welcome.

You can look at pics of the boat running yesterday and the highest temp readings here.... http://www.gokartracing.org/1984bayliner.htm

Thanks
Tom
 

captmello

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Re: Help with 270 and AQ 125

Isn't there a drain on the tube going from the heat exchanger to the exhaust manifold? You could open that drain and see if the water drains quickly out from there first to try to isolate the blockage.

It sounds like your on the right track.:) Now that your an expert and all...;)
 

skagitcom

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Re: Help with 270 and AQ 125

Yes there is a petcock. There is one in the tube and one on the bottom of the exhaust manifold, very close to each other. I have not tried to turn them except by hand. I'll try both today.

I was not to eager to put very much water in the tube when the engine isn't running for fear of water going into the exhaust ports if there is a blockage that could cause that.

:rolleyes: I felt that one.. ;)
 

captmello

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Re: Help with 270 and AQ 125

I would try draining both. Just to see what you find. You'll need to drain those both to winterize eventually.
 

skagitcom

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Re: Help with 270 and AQ 125

The rest of the story..........

I didn't want to post to much and make this a novel so I waited until I had the problem solved this time.

The next day after my last post, I pulled the exhaust manifold and found that it was partially blocked right where the water comes into it from the heat exchanger. Luckily I have a after market manifold that has screw in plugs. Three on the outside and three in the engine side, plus the brass plug with the zinc attached. I tried to find a shop that would boil it out but everyone told me that would do no good for rust. As it didn't look like there was much other than right where the water sat at the bottom rear, I was able to poke and prod, and hit it with a hammer knocking all kinds of scale loose. I must have spent several hours cleaning and flushing with a garden hose. Shortly after I started it was flowing good enough to use.

I replaced both brass petcocks. One on the exhaust manifold and one on the bottom of the exchanger output copper tube.

Yesterday I put it all back together after waiting for exhaust gaskets and a raw water pump seal. It started raining as I was finishing so I waited untill today to finish.. I started the motor and checked for leaks. Finding one at the brass pipe petcock, I resealed the threads and all was good for the lake.

A friend came with me and we ran it around a local lake East of Mount Vernon, WA called Big Lake. I could run it all day now at 3500 to 4000 with the temp not going above 180. The boat comes up on plane at 3000. I guess the motor will run up to 5000 I have been told but it doesn't seem to need that RPM to feel like it's running 25 or so (no speedo and forgot my GPS). After a half hour of running it had one other small drip comming from the cover gasket on the raw water pump. When I took the pump apart to remove and replace the seal I used the old gasket. That will be easy to fix.

Thanks for all your help and suggestions. Everyone had good suggestions and I was led in the right direction.

If anyone needs any AQ125A parts I have several spare pieces and know where the parts can be found at the very best prices. I paid way too much for some of my parts, but I was in a hurry to get it done.

Tom
 
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