AQ131

[Rmac]

My 1986 Aq131, is running hot under a load,, it's fine while sitting at idle. I have replace the Seawater pick up impeller,, clead the heat exchanger,, and it still runs hot. No water in the oil, I have also replace the elbow on the out drive that broke or corroded away. HELP PLEASE<br /><br />RM

 

[Walt T]

Re: AQ131

Make sure the heat exchanger isnt plugged and change the thermostat.

 

[Rmac]

Re: AQ131

Changed the T'stat and cleaned the heat exchanger,,,Do you all theink maybe a bad exhaust mainfold???<br /><br />Thanks <br /><br />RM

 

[Walt T]

Re: AQ131

Anything is possible, but I'd still suspect the heat exchanger.

 

[Larry S]

Re: AQ131

I had the same problem with my AQ131. After waisting half a season cleaning the heat exchanger and changing the themostat and checking the hoses for sucking air and replacing the impeller, I found my problem to be a restricted exhaust manifold. Just clogged enough to raise the temp while under load. Proved this by opening the petcock under the manifold while under full power.The bilge pump was able to pump the water out while leaving this petcock wide open. Temperature never went above 180 while doing this. I bought a new manifold and now it runs around 180.

 

[johnkc]

Re: AQ131

very possible that it is the upper bushing on the water tube out on the drive.it is located under water neck that the rubber hose attaches to. to check,ENGINE OFF. install flushette and plug the hole in the bottom of the drive so that you can force as much water as possible towards the engine .you will have to hold the cups of the flushette tight to the lower unit .then look where the water neck attaches to the drive for a water leak.good luck.

 

[imported_Mike_M2]

Re: AQ131

I have worked on a lot of these, my bet is the exhaust manifold. Try removing the tube from the exchanger and blow into the manifold with it. If it's hard to blow, there's the problem. The smallest clog is enough to heat her up at high rpms.

 

[Walt T]

Re: AQ131

Looks like I'm outvoted. Check those manifolds.

 

[imported_Mike_M2]

Re: AQ131

Diesel, those exchangers were a problem too! One little bit of mud near the outdrive and they clogged. I notice that guys clean them, try it, they still overheat, they clean it again. If you can blow thru the exchanger with little resistance, it's time to look elsewhere. <br />I have also seen a few where the pivot point on the outdrive will sick in air. The water intake is in the middle of the pivot tube, and since the impellar is engine mounted it sucks air. This only happens when you get on plane, because the pivot is under water at idle. If the manifold isn't clogged, that's the next thing to check.

 

[Rmac]

Re: AQ131

Thanks guys ,, looks like it $249 for an exhaust manifold..<br /><br />RM

 

[Larry S]

Re: AQ131

Would like to know how you make out, so keep us posted.

 

[johnkc]

Re: AQ131

Rmac ,how did you get the diagnosis that it IS the manifold for sure?

 

[Rmac]

Re: AQ131

Well first I have already cleaned and flushed the heat exchanged ,, more than once, second my raw water pump is new,, I have already replaced the elbow on the top of the out drive for the water line, what else can it be?? anymore suggestions would be welcome. and I have replaced the water pump on the motor. So everything is either new or has been cleaned and flushed. Thanks for all the replies<br /><br />RM

 

[Peter J Fraser]

Re: AQ131

Is there a possibility of any water hoses on the suction side of your sea water pump collapsing with suction pulled in the line and restricting water flow to your SWP? I have seen this happen on my AQ170 on the short run of hose from the transom shield to the pump inlet pipe. Ordinary auto water hose hasn't got thick enough walls to run with suction.<br /><br />I have replaced mine with a hydraulic suction hose with more reinforcing braid in the walls.<br /><br />Good luck.<br /><br />Peter

 

[imported_Mike_M2]

Re: AQ131

RM, do like i said and blow thru the manifold. Blow thru the metal tube on the bottom of the manifold by removing the end from the exchanger and swinging it out. If it's hard to blow, it's clogged. You should be able to blow and hear water bubbling or just air. If it's clogged, replace it. If it isn't try checking for air leaks in the outdrive. Do this by removing the hose going into the pump and connecting a garden hose to it, forcing water back into the drive. Plug the intake at the bottom of the drive(both sides and the hole on bottom if you have one). Kick the hose on and look for water squirting out the point where the drive pivots for steering. If it leaks anywhere other than where you plugged the intake, you need to fix it. Those drives were like a straw, if there's a slight air leak it will not suck water up.<br />Since you have replaced the impellar and cleaned the exchanger, these are the only other problems i've ever seen.

 

[Rmac]

Re: AQ131

Thanks Mike , i'll try that this wwekend,,,and see what happens I'll keeo ya'll posted on this<br /><br />RM

 

[johnkc]

Re: AQ131

Rmac, install a clear piece of hose in place of the black hose that goes from transom to engine. <br />[water supply hose]then take the boat for a test ride and watch that clear hose for air bubbles going thru it.make sure you get on plane.there should not be any air bubbles flowing thru this hose.