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volvo penta 1986 AQ131 air in uptake tube

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wibeaux

New member
Can anyone help? I have 1986 Bayliner Capri 19 ft . It is old, but has few hours on it. Main problem is overheating after being stored: visible air in uptake tube(when clear tube installed for diagnosis by 2nd opinion tech. Has been in first shop two years...said they replaced uptake tube, water pump, thermostat...had the second opinion last month. He said still sucking air when planing, so 1st shop did not correct problem. He towed it back to first shop to fix it. I am overwhelmed and am seeking another shop to fix what first shop did not fix. Suggestions very much ppreciated. Thanks!
 
Re: volvo penta AQ131 air in uptake tube

I would bet you a beer that either the raw water hose connector in the outdrive intermedite assembly is perforated, or the beaded gasket is worn. That would cause the raw water pump to suck air when the boat is on the plane. These are parts 27 and 28 in the picture. The Sierra part is 18-2778, check this link.

http://www.marineengine.com/parts/p...78&returntopage=sierra_marine/sierra00856.htm



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Re: volvo penta AQ131 air in uptake tube

May also want to look into a through hull water pickup, I did it on my aq131b and has solved alot of my over heating issues!!! You might want to check out this website. WWW C P Performance.com thats where I got mine, also alot of times the exhaust manifold (water jacket) will get clogged a little and thats enough to make it over heat!!
 
Re: volvo penta AQ131 air in uptake tube

Thank you for your info. It looks promising. Now the trick is to find a shop I can trust. Is a AQ131 the same as AQ131A? The Thermostat Housing # 18-2778 does not show a AQ131, but there is #18-277 listed for AQ131A. I'm hoping they are the same. Maybe this will help whoever get the right part. Thanks, again!!
 
Re: volvo penta AQ131 air in uptake tube

The 18-2778 is a universal replacement but the other one (18-2777) will also work.

Portagie, you are correct. The exhaust manifold, if clogged, can lead to overheating; and so can a choked raw w ate strainer, a faulty raw water pump, and a few other items. However, I believe we are talking about air being sucked into the raw water system, so you have to look from the raw wapter pump suction side to the water intake grids in the lower gear assembly. The vast majority (not all) of the overheating problems in the AQ series can be traced to a faulty raw water hose connector as well as to the beaded gasket not sealing around the water tube.
 
Re: volvo penta AQ131 air in uptake tube

wibeaux said:
Now the trick is to find a shop I can trust.
Click to expand...

You can do that job yourself, it is not tat complicated. You just need to lift the outdrive and use a 3/16" allen wrench.

Check this

http://www.marineengine.com/boat-fo...highlight=connector+perfect+seal+allen+screws

http://www.marineengine.com/boat-forum/showthread.php?t=81833&highlight=water+hose+connector+allen

http://www.marineengine.com/boat-forum/showthread.php?t=83944&highlight=3/16+allen+screws
 
Re: volvo penta AQ131 air in uptake tube

What an idea! I'm a woman with limited experience with engines, but I can use an allen wrench...and a few other tools. Maybe I could do just as well as the company that has had my boat...that is, with the help of this web site and the assistance of its members. Thanks!
 
Re: volvo penta AQ131 air in uptake tube

One company has refused to look at it...too old, does not have the special tools it would take. I understood that I could use common tools to do this replacement. If so, maybe I can get a neighbor to look at it or try it myself. What is your impression? Thanks.
 
Re: volvo penta AQ131 air in uptake tube

Here is the hose connector (water neck) and water hose. You can also see the hose clamp for the water hose with the slotted screw pointing downwards (3 o'clock looking at the outdrive from behind). It is very important that you install it again that way.

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Here is how to access the starboard side allen screw with a 3/16" allen key.

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And here is how to access port side.

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Once you have the water neck and the hose out, just unscrew the hose clamp, remove the old water neck and intall the new one (coat both the first 1 inch inside of the hose and the water neck areas where it mates with the hose and the beaded gasket with Permatex Aviation Gasket or Loctite Gasket Compound or Quicksilver Perfect Seal or similar). Then remove the beaded gasket on top of the water tube, clean the drive surface where the gasket seals and coat it with the same gasket compound as above, then coat the new gasket with gasket compound, then put it in place (rib pointing downwards), then install the water neck on top and tighten well the allen screws.

You are done.

As you can see it is a neasy process and no special tools are needed.

If you don't feel confident to do it yourself, perhaps you may want to print this and show it to a neighbour who can do it for you; or even to a marine shop if no neighbour or fried will do it.

Good luck.
 
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Re: volvo penta AQ131 air in uptake tube

Your pictures are great! Thanks so much! My neighbor will talk to a friend of his...see if he can look at it. The shop said they replaced tube, but I don't think they did anything regarding rings, or did not say so. Bad o rings and gaskets all make sense. One reply mentioned impeller. Would bad impeller cause more air than water to be in tube? If so, where is impeller on diagram? Could not tell by numbers. You have been a great help, el pescador. Wish you were on the opposite side of the continent!:)
 
Re: volvo penta AQ131 air in uptake tube

I have a Clymer/Volvo stern drive manual, but cannot find any directions to replace tube, o-rings, impeller. Would this be in a special manual? or can I find it online? I was told that the water pump was replaced by the shop. PS engine has AQ131A on label, so now I know that much! Thanks...again and again!
 
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