volvo penta 225d impeller problems

[jackay]

Hello,
I have a 1978 volvo penta 225d/280outdrive. I am new to boats but understand a little due to this problem. I went to put the muffs on the outdrive and am getting no circulation through the motor. Impeller was the likley culprit so I replaced it. Still no water flow back out the outdrive. I pulled hose ends off the impeller and ran the motor (very shortly) to see if water flow would shoot out, to isolate blockage and very little would come through. Black water runs out of the elbows that receive water into the manifolds but no water seems to make it up to the 4 ported block that seems to contain a thermostat after the impeller pump and before the motor's water pump. What do I do next? Could the impeller still be failing to do its job or should I think about blockage before the impeller? Or something else?

 

[SS MAYFLOAT]

Re: volvo penta 225d impeller problems

Welcome aboard iboats!

Have you tried hooking your water hose to the hose on the outlet side of your pump? This would bypass the pump to help further your troubleshooting. Black water does not sound good. Has this boat been used in salt or fresh? Salt will cause corrosion and the fresh water lakes now have zebra muscles that will clog up exhaust manifolds and other passages.

I have the same setup that you have. I ran mine without the thermostat, but the boat ran cold. Put a new stat in and I noticed that until the engine warmed up to 160* there was not much flow out the exhaust. Hopefully you can get it cleared if it is a blockage.

Don S will be online and he can shed some better light on your problem.....Good Luck........SS

 

[jerryjerry05]

Re: volvo penta 225d impeller problems

If you have the wrong muffs you might not be picking up correctly.
You need to duct tape the muffs on a dry outdrive(wet wont stick)
The very bottom of the drive in the front there is a 1/2 in hole that needs to be blocked it's the drive drain,there to allow water to leave the OD.It will suck air from there.Try the tape and plug the hole( a tip from a small silicone sealer container fits right in there)

Let work the water pump.If the old impeller came out whole then the possibility the cam is worn and not compressing the vanes in the pump.If the WP cover has a lot of wear and scratches it will suck air there too.The impeller cavity could have scratches in it too.Minor stuff is ok.Just deep scratches will hurt.The pump shaft has a seal at the end of the shaft this could be sucking air too!These parts avaiable and aren't too expensive.A lot cheaper than a whole pump.If you run into a lot of shallow water install a seastrainer to keep the junk out of your pump.Jerry

 

[Don S]

Re: volvo penta 225d impeller problems

I've never had to tape on muffs, but the short Volvo muffs do come with a bungee cord to hold them on. but you do need the plug the secondary pickup.

One othe problem that is common on those drives is the water hose connection on the drive. They corrode away where the hose connects and all your pump will do is suck air.

 

[Maclin]

Re: volvo penta 225d impeller problems

Try the methods jerryjerry showed you. The Volvo drives are hard to match muffs up to and that drain hole can let air in and break suction.

If you still get little or no water flow then you can find a hose that fits the intake side of the raw water pump (where the impeller is) and run that into a bucket of water and see if you get good water flow that way. You should get a LOT of water out the back, if so this will eliminate the pump as the problem.

There is a document that Don S has hosted and provided a link to, it is a cooling system troubleshooting guide right from Volvo, a search thru recent thread should reveal it.

There are other components from the drive to the pump that can be problems. There is a fitting on the drive that can corrode and let air in. The molded hose from the drive up to/thru the transom can be corrupted. The fitting on the inside of the transom could be corrupted or the long hose from that fitting up to the pump can be corrupted. Any of these would let air in and break the suction. That document has procedures for testing all of that.

The method I used was I found a tub big and tall enough to submerge my entire duoprop drive up to the cav plate and well over the intake grates and tested mine when I had the poor flow on the muffs. I had just replaced several components and still had poor flow on the not-for-Volvo muffs I had and wanted to be sure how it would behave in the lake. This was before I had learned of the drain hole plugging. If you do try this at home don't put it in gear!

 

[Maclin]

Re: volvo penta 225d impeller problems

Man, it takes me a long time to get my posts typed in! Don had not responded yet when I started my other one, good stuff to try, good luck!

 

[jackay]

Re: volvo penta 225d impeller problems

Thanks for all your responses,i'll keep eliminating things and get back to you. This is a big help I did eliminate the long intake for the drive as being pluged as I took off both ends and ran water through it, the wear plate? (small set screwed plate in the impeller housing) looks worn a bit but not bad and there seems to be not scratches in the housing itself. Is the water pump on the motor itself doing any work with the impeller to suck water through?

 

[jackay]

Re: volvo penta 225d impeller problems

I figured it out sort of. I disconnected the intake hose from the outdrive and placed it in a 5 gallon bucket to test the impeller. It worked great and pumped water through the motor and out the outdrive. Then hooked it back up properly and still no suction to the impeller. Then I notice a series of leaks in the intake hoses on the outdrive and on the exhaust hose (big 4 inch hose). I'm guessing that it's sucking air from a hole in the intake hose? is there any other parts or valves that are inline from the garden hose intake to the impeller?

 

[Maclin]

Re: volvo penta 225d impeller problems

This is from my previous post...

"There are other components from the drive to the pump that can be problems. There is a fitting on the drive that can corrode and let air in. The molded hose from the drive up to/thru the transom can be corrupted. The fitting on the inside of the transom could be corrupted or the long hose from that fitting up to the pump can be corrupted. Any of these would let air in and break the suction. That document has procedures for testing all of that."


The test for this is to tape up the intake grates on the drive and plug up the drain hole on the front of the torpedo, then on the inside remove the hose from the inlet of the raw water pump, the one that comes from the transom, stick a garden hose in it and run water backwards thru that part of the system to see if any water comes out and where.

 

[Maclin]

Re: volvo penta 225d impeller problems

This is a link to the post that contains the link to the Volvo Penta Overheat Diagnosis document that Don S has hosted for interested parties, you can down load it from there, well worth the effort and disk space....

http://forums.iboats.com/showpost.php?p=1710757&postcount=20

 

[JAL51974]

Re: volvo penta 225d impeller problems

I hooked up a vacuum to the water hose on the right side of the engine, then covered the outdrive areas where the water sucks up into that water hose with a little white shaving cream. The normal water intake vents were taped over at the bottom of the drive. Running the shop vac on that line let me see and hear exactly where the leaks were. Then it is a matter of isolating those parts and replacing rubber gaskets, washers, etc. The biggest culpret is that water intake hose fitting that is connected to the rubber water hose on the drive itself, it is the smallest one of the three hoses- the other two are for the exhaust and for the u-joints.