Volva Penta adaq31a - overheating

[rewopem]

My adaq31a overheats when run at cruising speeds. Ok at idle and lower speeds. The flapper in the riser is rusted off and no where to be seen. Suspect this is blocking water flow and causing the overheating condition. My question is: how does one check this out and remove if applicable.

 

[sqbtr]

Re: Volva Penta adaq31a - overheating

Never heard of a adaq31a, got any pics?

 

[Don S]

Re: Volva Penta adaq31a - overheating

I think he means AQAD31A, which is a 4 cylinder diesel.
So I will move this over to the diesel forum.

There are no exhaust flappers on those engines. Have you replaced the impeller?

 

[rewopem]

Re: Volva Penta adaq31a - overheating

You are right it is an AQAd31A and I'm sorry but there was a flapper there that has rusted off.

 

[Don S]

Re: Volva Penta adaq31a - overheating

Post some pictures. Because Volvo did not use exhaust flappers except on the drives.

 

[rewopem]

Re: Volva Penta adaq31a - overheating

Don ... I think we identified the problem with overheating but unsure of how to go about fixing it. It's a VP 290 stern drive. When you feed water backwards from the engine side the water flows ok but leaks around where the hose is connected to the transom. The pipe over which the hose fits seems to be the problem. Is there any easy way to get at this without having to take the drive off the boat ?

 

[Don S]

Re: Volva Penta adaq31a - overheating

Just remove the upper gear box for easy access to the hose connector. While there, if your ujoint bellows is over a 2 years old, replace it while there, along with all orings and gaskets.
Here is a thread covering the job. It's a really easy job.
http://forums.iboats.com/showthread.php?t=309095