AQ231B 88' not overheated yet, but not pumpin water.

[mfsb]

Hello everyone, want to say thank you first for all the wonderful posts it is helping me with my own troubleshooting and repower. I have a 1988 VP AQ231B, that had a cracked block. I have since replaced the long block with a chevy 350 from a 1987 truck that I had rebuilt. I stressed to the engine builder it was for a boat and needed the proper cam. Everything else has bolted right up and doing great. I finally got it started and running today however it isn't pumping water.

I have replaced the impeller on the raw water pump attached at the front of the engine on the crank, have replaced the thermostat and have filled all the hoses with water. With muffs on the outdrive I noticed water coming from the bottom of the leg from a hole I believe is supposed be a suction spot also. I then plugged that so the water would come from the muffs and still not pumping. I am going to remove the thermostat and verify it is installed properly and also start tracing the water lines from the powersteering cooler forward to verify they are allowing flow from the water. Next, I plan on taking the output from the raw water pump to the circ pump and filling it with water and seeing if it leaks, veryfying hopefully it isn't just sucking air from a bad seal on the pump. While I had the engine out and pump off I verified the bearings and such and they are very smooth and the raw water pump seems to be in good shape, especially with the new impeller.

A question I had about the raw water pump is that with the engine running it seems to be off center a bit, as if it is bent or out of round on the mount, I hope that isn't a problem. I also wasn't sure where else to look for troubleshooting the heating issues any ideas would be great. Don has posted several times of the photo with the alternator on the bottom of the engine port side, that is the one I have and hope to get running properly. Thanks again.

 

[Don S]

Re: AQ231B 88' not overheated yet, but not pumpin water.

A question I had about the raw water pump is that with the engine running it seems to be off center a bit, as if it is bent or out of round on the mount

The pump is not installed correctly. There are a couple of bosses sticking up on the pulley behind the pump. The pump base has a lot of holes in it, the bosses in the pulley needs to fit the holes in the pump. If not, it will wobble.

For your water problem, check the hose connection just under the upper gear box on the drive. The connector corrodes away and allows the pump to suck air, not water.

 

[mfsb]

Re: AQ231B 88' not overheated yet, but not pumpin water.

Thanks don for the help on the pump. I pulled it off and saw in my haste how I had not assembled it onto the engine properly. I also pulled the thermostat housing and the thermostat only fits one way, the element faces you when you are lookin at it. I also am verifying it opens at the proper temp on the stove but it is brand new so I suspect it is fine. I am now also going to check for poor suction or blockage at the powersteering cooler, not sure where else to look. Maybe at the raw water hose pick up, I resealed it but will double check it. It is mounted on what appears to be a joined tube going into the lower outdrive, is that replaceable? maybe that is my problem? Thanks again for your help.

 

[mfsb]

Re: AQ231B 88' not overheated yet, but not pumpin water.

just test ran the boat, it is still tryin to over heat, temp gage shows 180, temp probe verifies it is getting that hot. Thermostat was checked on stove with candy thermometer, it is a 140 degree, workin like a champ. The pump no longer wobbles now only thing I can check is an obstruction in the line. I replaced the impeller as part of the engine replacement so I am sure it is good. Does anyone have any suggestions on where to start, first thing is pullin that powersteering cooler after the engine cools down not sure what else to look for.

 

[mfsb]

Re: AQ231B 88' not overheated yet, but not pumpin water.

so was lookin at the water pump diagram, could a bad circulation pump be causing my heating issue? going to back flush all the water lines from the raw water pump to the pick up in the mornin, but I don't where else to look if I find good flow. Thanks for the help.

 

[captmello]

Re: AQ231B 88' not overheated yet, but not pumpin water.

Maybe at the raw water hose pick up, I resealed it but will double check it. It is mounted on what appears to be a joined tube going into the lower outdrive, is that replaceable? maybe that is my problem? Thanks again for your help.

the intake can cause overheating if it is sucking air. Check all you connections. Are you testing on water or on muffs?

 

[mfsb]

Re: AQ231B 88' not overheated yet, but not pumpin water.

So here is what I have done so far. I put the garden hose down the hose to back flush anything out right at the connection on the intake side of the powersteering cooler. No obstructions found and water flowed cleanly out. I then put the garden hose on the output side of the powersteering cooler going to the raw water pump. Of course it over flowed a bit into the bilge and I let the drain out. I then started the engine and it was now running quite cool. I let it run for about 10 mins, had no issues, engine warmed to 145 roughly and didn't have any problems. Water was coming out of where it was supposed to and I revved it a bit to see if that affected it. Ran it all the way up to 3500 rpm and let it sit there for a couple mins with no temp issues, it didn't show higher than 150 on the gage at all. I thought maybe it was doing great now, so I took it to the lake. Put the boat in the water with the outdrive fully submerged and ran the motor, this time it wanted to over heat and I shut it off at 175 ish, it wanted to get hotter and I didn't want to hurt anything. I let it run just long it enough to see that it was tryin to over heat. My question now is since I replaced the impeller already for the raw water pump is it possible my circulation pump is bad? If not do I need to possible replace the whole raw water pump assembly? I am not sure which one to check, I am guessing I have a pump/ suction issue, I figured putting it in the water would over come any chance it was sucking air at one of the parts on the outdrive, since the outdrive was fully submerged. Any advice would be greatly appreciated.

 

[mfsb]

Re: AQ231B 88' not overheated yet, but not pumpin water.

just wanted to update, my thought process on putting boat in the water to troubleshoot was that if I had the whole outdrive submerged I would be able to force it to suck in at points it maybe be leaking air into the system on the outdrive unit. for example if you take a perforated tube and stick it in the water past all the holes it will suck water until you expose the holes. That has had no effect for me, so I would guess that either of the pumps aren't workin properly or I have air entering at a different location. I am hoping someone on here has had a similar issue or could point me in a direction to troubleshoot each individual pump. Thanks for your help.

 

[captmello]

Re: AQ231B 88' not overheated yet, but not pumpin water.

If it didn't overheat while it had the water flowing into the intake hose, in the bilge, then it seems the issue would be at the outdrive. However you tested it in the water, with the outdrive submerged and still overheated. If this is true, you should have blockage in the outdrive, or perhaps the s shaped hose is kinking when in the water...

Just guessing.

 

[mfsb]

Re: AQ231B 88' not overheated yet, but not pumpin water.

I have been reading lots today about the tube in the out drive. I don't have the boat with me but can I replace it and the gaskets without pulling the drive? Figure I would order the tube, s-tube, and seals to have them waiting for me to get home.

 

[Merc_115]

Re: AQ231B 88' not overheated yet, but not pumpin water.

mine sits at 180 also on muffs, i thought this was fine, i see no water coming out of outdrive like my outboard

 

[captmello]

Re: AQ231B 88' not overheated yet, but not pumpin water.

mine sits at 180 also on muffs, i thought this was fine, i see no water coming out of outdrive like my outboard

do not confuse this engine with your 125. The 231 is raw water cooled and should run cooler than the 125.

 

[mfsb]

Re: AQ231B 88' not overheated yet, but not pumpin water.

yeah with the garden hose inserted at the hose connected to the powersteering cooler I ran at 140-150 for about 10 mins with no issues, water was flowing properly from exhaust and outdrive. I had no issues with temp, stopped after 10 mins so I could attempt to continue troubleshooting the engine. I haven't run it past 180 because I don't want it get hurt while I know it isn't working properly. I expect it to run in the 150s ish when operating properly.

 

[captmello]

Re: AQ231B 88' not overheated yet, but not pumpin water.

I have been reading lots today about the tube in the out drive. I don't have the boat with me but can I replace it and the gaskets without pulling the drive? Figure I would order the tube, s-tube, and seals to have them waiting for me to get home.

I hate to see you through parts at it, If it is overheating with the outdrive submerged in the water, I don't think the problem is sucking air. You've back flushed through the outdrive correct?

Which Tube are you referring to in your previous post? The S-hose could be collapsing when the pump is trying to draw water up...Hard to say from here.