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kraftee
08-02-2013, 09:00 AM
My 18 has an '88 Volvo SP-A drive (stroked sbc - raw water cooled - freshwater use ONLY) which has been absolutely bullet-proof, but I have run into a situation I cannot figure out. Hoping one of the Volvo gurus here on the board can help. The other day, we spent the afternoon anchored and relaxing. The drive was down in the sand - but the motor was not running. Left there and ran the 8 miles down to the other end of the lake and crossed slowly through a weed-infested area before powering back up and running back towards my home dock at about 3200 rpm. About a half-mile before I got to the dock i noticed the engine note got a bit louder through the open exhaust. I just assumed that the wind was blowing a bit harder in the direction I was running and thought no more about it as I had my hands a little full avoiding some idiot letting his 10 year-old drive his Sea Ray and a bass fisherman blocking the entrance to my lift. Anyway, as I pulled onto the lift, I smelled a bit of a burning rubber smell, glanced at my gauges and saw the temp was pegged. I shut it down and got lots of steam. Crap.

I immediately assumed that I had somehow clogged the intakes - either with sand or with weeds, and burned up the impeller. So, ran to the local marine store, got another impeller and changed it out. The old impeller was chewed up a bit - but not completely gone. Started up and still not pumping water. I pulled the hose off the pressure side of the raw water pump. Started up again. No water. Pulled the boat up out of the water and put the muffs on the lower unit (and of course, the blocking peg in the bottom of the leg.) Started it again. Still no water. Pulled the suction side hose off the raw water pump and turned on the water pressure to the muffs. STILL no water. Maneuvered the suction hose to where I could blow through it and everything seems clear. Put the garden hose into the suction side hose and the water comes right out through the lower unit.

I have had this lower unit off at least 4 times since I have owned the boat and all hoses are less than 3 seasons old. Any suggestions on why water won't come through the drive with the muffs on, but water will flow BACK through the drive (there isn't some sort of "one-way" anti-syphon valve on this drive, is there?) Hoping like hell that once I get THAT issue figured out and cooling water flowing back through the motor, that I haven't warped my aluminum heads...

Thanks for any and all suggestions.

ERIC

mattyboy
08-02-2013, 09:38 AM
Personally I have never had luck running a aq Volvo on muffs. I would remove the intake hose from the drive stuff the hose in there and tape it up turn the water on low and see the block will fill and dump water out the back might not be a bad idea to break the system at it's connections into the pump out of the pump to see the flow of water
If you get it pumping water on the hose reconnect everything and dunk the boat on the lift sometimes it takes gravity to start the syphon in the drive

Also check the water outlet on the drive that passage is pretty tight so weeds and sand could block it

Good luck keep us posted

kraftee
08-02-2013, 11:00 AM
Thanks for the suggestions Mattyboy. I will certainly try everything you mentioned. However, I have always had good luck running this particular unit on the muffs. I just cannot figure out why, with good hose pressure - and holding the muffs tightly against the drive, I cannot get water to go up through the drive and into the boat (with the hose disconnected from the RWP.) Your last suggestion was to check "the water outlet on the drive". Which outlet do you mean? With the muffs on the unit, the ONLY place water is coming out is around the muffs - even though I am squeezing them tightly against the intake grills. Do you think that the hose between the leg and transom shield could have collapsed internally? I am pretty baffled, but will post back if I get a chance to work on the boat later this evening. Thanks again.
ERIC

mattyboy
08-02-2013, 11:35 AM
there should be a hose coming from the transom housing inside the boat that should go to your raw water pump or circ pump depending on if your setup is a crossover system. There is a gooseneck that comes thru the transom housing that the hose should be connected to. on the outside of the boat there is a small hose that goes from the drive to the other side of this goose neck. This would be the water outlet of the drive leg to the intake of the motor.

if the water intake hose on the inside of the boat is disconnected from the transom housing and you put the garden hose inside this hose and tape it up you should be able to push water by the pump and fill up the block and then the water should dump out the back.
be careful if your garden hose has a lot of pressure you could damage things. That is why I said low or half pressure on the hose. If this happens you should be able to run the boat on the hose my motor runs about 140 without a t stat and about 170 in the 80 degree lake, mine is a ford with a cross over .

This is also where a flush valve helps , it is cut into the intake hose between the drive and the motor and will hook up to a hose it closes the drive end and routes water to the motor when there is hose pressure if not the drive end is open.


please note this is on a AQ200-280 I am not totally positive that it is the same on your AQ290 but I think that is one of the things that wasn't changed

MOP
08-02-2013, 03:52 PM
Take the hose off coming from the drive at the pump and back flush the drive, it does not take a lot of junk to cut the supply to the pump.

Phil

SanDogDewey
08-03-2013, 01:01 AM
My 270 runs good on muffs. I always plug the hole in the bottom of the drive. A Sharpie fits perfectly.

silverghost
08-03-2013, 03:24 AM
There is No one way water inlet check valve in that outdrive~~~

It sure sounds like the outdrive's cooling water inlet passage or outdrive to transom shield special Volvo hose is still partially plugged-up with weeds, sand, mud, or debris.

The special odd shaped Volvo outdrive water inlet 1" hose that goes from the outdrive to take water from the lower unit's pickup holes to the transom shield mount and allows the outdrive to swing from side-to side and stear, & also tilt & trim could possibly be at fault.

When those hoses gets old they can kink, crush, get stiff , or collapse and not allow water to get to the engine's seawater pump from the outside outdrive.

Lot's of folks also use a standard auto parts store hose which sometime do not work very well for this sort of application.

Re; Clogged outdrive & inlet
You may have sucked-up sand, mud, seaweed, weeds, plastic bags, etc from running the outdrive in low water.
The outdrive's inlet water passage or drive's inlet hose may be partially packed with debris. Try backflushing it by removing the engine's seawater pump's inlet hose and run full flow from a garden hose backwards through that intake hose & the outdrive.

Re; Impeller
Did you find ALL the old rubber vane pieces from that burned & ruined water pump impeller ?
One stray broken rubber impeller vane, or pieces of a vane may be blocking the engine's or oil cooler's proper inlet cooling water flow ?
Usually these stray broken blades wind-up somewhere downstream from the pump~~`One is sometimes all it takes to cause overheating.

Did you lube the new replacement impeller with liquid dishwashing soap or silicone grease (silglide ) to help start the suction prime of the sea water pump ?

Re; Thermostat
You may also have damaged your engine's thermostat by severe overheating. I have seen thermostats blow apart; & the broken thermostat parts block waterflow from severe overheating. If a thermostat severly overheats beyond it's fully open position it's temp sensor power pellet keeps expanding and actually breaks the thermostat into two pieces.
I have seen this happen more than once.

Long Shot ~~~
I have also heard of mud dauber wasps partially or fully plugging up the outdrive's water inlet & internal cooling water passage holes ~~~but only after the boat has been sitting on land for some time in storage~~~surely not the case in your situation .

kraftee
08-03-2013, 06:47 AM
Thanks SIlverghost. That's EXACTLY the kind of advice I was looking for. I am also pretty sure that it has something to do with that Volvo hose between the outdrive leg and transom shield. I have already tried backflushing with a garden hose, and water DOES come out of the leg as expected. But as soon as I put the muffs back on, I cannot get water to come through the transom shield. So I don't know if I am just moving the clog back and forth. I bought a length of 1" hose yesterday and will try backflushing again. Otherwise, I guess I will have to tow the boat over to the ramp so I can put it in my garage and yank the outdrive leg off. Then I can remove and inspect that hose...

Thanks again everyone for the helpful suggestions! I will keep you posted.

ERIC

kraftee
08-03-2013, 06:52 AM
...oh, and there were no vanes missing from the impeller - it was chewed up a bit, but nothing large had been torn from it. Have changed LOTS of impellers in my other job as a charter yacht captain taking care of a fleet of charter yachts in the Bahamas! Have had to spend lots of time hunting for all the broken off bits over the years!

joseph m. hahnl
08-03-2013, 09:53 AM
Stick a electrician's wire snake gently down the out side to feel for a blockage .In theory nothing larger than the inlet screen should be able to enter. Sand may have ruined the impeller housing . If Vacuum pressure exceeds inlet flow the inlet side of a hose will collapse not the outlet side. The same token goes for the engine circulator pump. If it draws more then the supply, the hose will collapse. I never worked on a Volvo drive, but most impellor housings are similar in design. You might want to inspect the impeller housing for the blockage .There maybe a small passage that is plugged up.

johnnywhale
08-03-2013, 09:54 AM
Eric
If it turns out you need the hose, let me know. I have a new one I will never use. Volvo # 875822-9. It's yours.
John
johnywhale@aol.com
http://i225.photobucket.com/albums/dd220/johnnywhale/IMG_2113_zpsb7c0514c.jpg (http://s225.photobucket.com/user/johnnywhale/media/IMG_2113_zpsb7c0514c.jpg.html)

gcarter
08-03-2013, 10:36 AM
I take it that we're not talking about passing gas here, and we're not talking about flatulence.....:wink:

mattyboy
08-03-2013, 10:50 AM
Kraftee
some more thoughts

remember this is a siphon system and you have some air in there now so back fill with water from just ahead of the pump I would think if it is blocked up it would be in the outlet of the drive where it makes a 90 degree turn in the pic it is 27 this is also a small dia spot . I also remember someone saying that on muffs their setup required a little blast of the throttle to start the flow. I would stay away from that until you know you have not fried anything. The volvo also routes the water intake thru the suspension fork. I guess to test that hook up the muffs and disconnect the hose that JW posted from # 27 and see if you get water if not I guess the drive is plugged. If you get water I would then connect the system one piece at a time until I get water to the pump. Hook up JW's hose and disconnect the hose inside the boat from the transom housing and see if there is water there. then continue downstream.

I would not run the motor without knowing there is water around the impellor that's why I said to remove the hose from the inside of the transom housing and force the garden hose up it turn the hose on and see what happens. I would check the oil level first before turning on the water just for piece of mind then check again after.

also check the garden hose without the muffs hold it near the bottom of the drive point it up and see how high it squirts, the muffs need to be super tight and sealed to force water to the top of the drive. maybe a big C clamp. I have seen a volvo not pump water dunked to cover the drive on a trailer once the boat floated free it pumped water.

good luck

mattyboy
08-03-2013, 11:14 AM
JohnnyWhale

I would like to place myself in line to purchase that water inlet hose if Eric doesn't take your generous offer

Thanks

kraftee
08-04-2013, 11:34 AM
Thanks for all the great advice guys. I hope to get back on it to try to get the problem sorted out sometime tomorrow. Thank you JohnnyWhale for the very gracious offer of the new hose, but I already have a new one in my spares kit, so go ahead and send it to Matty.

I'll check back in after I have the chance to work on the boat.

ERIC

johnnywhale
08-04-2013, 01:18 PM
Matty-
PM me your info and I will mail the hose to you, no prob.
Johnny

johnnywhale
08-06-2013, 10:08 PM
Eric,
I was talking to a friend, Ralph Sav on the board here, and he said the O ring seals at the steering mechanism will allow an airleak causing overheating / low water flow. Just thought.
Johnny

mattyboy
08-07-2013, 07:50 AM
That's a very good point might not notice it in the water but on the muffs the pump is sucking air into the siphon. those seals are on the water passage that goes thru the suspension fork. in the pic I posted it is under the part I highlighted. the seals look like 15 and 24

MOP
08-07-2013, 09:04 AM
Good call on the steering shaft seals, may or may not be the issue. Usually they will not have any bearing on water passing on the muffs, also at rest at the dock with the drive submerged they do not cause an issue. They start to suck air when coming on plane, making for an easy diagnosis.

kraftee
08-16-2013, 12:52 PM
Just wanted to post an update. I haven't been home to work on the boat for the past week or so as I was at a Factory Five Hot Rod Build School in Michigan (my next project.) Anyway, THANK YOU EVERYONE for all the well-thought-out suggestions. The boat seems to be fixed now. I believe there were two issues: First, there was definitely some sort of clog that caused the initial water starvation. Whether that came out when I slowed down and put the boat in reverse - or whether it came loose from all my high pressure hose muffs and sucking on the intake hose? Who knows. But, when I went to the local boat shop the day it all happened to pick up an impeller, they gave me one that they said was correct for my SBC Volvo. It was different from the one I removed by having more, shorter vanes (although the outside diameter was almost identical - thicker hub) and by being about 3/16" shorter front to back than the one I removed. Plus, it came with the wrong gaskets - so I had to reuse the old one. So, I don't know if THAT is why I couldn't get the motor to pump water after all.

Thought about this for awhile and ordered the correct Jabsco impeller, identical to the one that came out of the boat. Installed that today with a lot of (supplied) impeller grease and a new gasket. Left the output hose off and started the motor. It pumped a LOT of water immediately. Connected everything back up and warmed the boat up. Then backed off the lift and made a run around the cove. Seems to be absolutely fine as the temps are running the same as ever. Everything sounds fine and when I checked the oil after coming back in, there was no foam! So. Again. Thank you. This board is THE best resource for problems like this.

ERIC

johnnywhale
08-16-2013, 07:42 PM
Good - now go enjoy it!

72Hornet
08-20-2013, 08:33 PM
All great points on this thread for me to check on my 1972 270 drive. I had new bushings and hoses on the drive replaced 6 summers ago, so that may be the case. This year, we pulled the thermostat equalizing springs in the elbows and tested them in a can of water and they open as they should. We installed new bearings in the impellor as they were a bit loose. When we run it on the muffs, I plug the very bottom hole and use duct tape for the muffs. I do not spare any tape for this and it all seems to cool fine on the trailer. We ran it for 30 minutes like this. This may be a late Fall project for me! Thank goodness that I have the 1968 18 running well and two wood boats to fall back on. Any thoughts, I would welcome!