Running on muffs

[StealthQ5]

I have a 2013 4.3L TKS with an A1G2 drive. Sorry if this is too basic but I am new to sterndrives. I just did an impeller replacement a week ago. Boat was winterized, and I haven't yet had it on the water this year. I ran with hose/muffs the other day. I got water sputtering out of the gimbal housing, which then got hotter over the next several minutes. I have not run on muffs before. When the engine got to temp at idle (gauge showed just under 180F, and held there) the water sputtering stopped at the gimbal housing. Is this normal? Where should the water be exiting? Thanks

 

[alldodge]

I have a 2013 4.3L TKS with an A1G2 drive. Sorry if this is too basic but I am new to sterndrives. I just did an impeller replacement a week ago. Boat was winterized, and I haven't yet had it on the water this year. I ran with hose/muffs the other day. I got water sputtering out of the gimbal housing, which then got hotter over the next several minutes. I have not run on muffs before. When the engine got to temp at idle (gauge showed just under 180F, and held there) the water sputtering stopped at the gimbal housing. Is this normal? Where should the water be exiting? Thanks

Howdy

Sounds like you might not have got the water tube lined up correctly, items 29, 30 and 31
http://www.mercruiserparts.com/bam/subassembly/30862/2686/140

Was the water running out the prop hub?
Was water spraying out around the muffs?
Was the water on full open?

 

[StealthQ5]

Water was not coming out of the prop hub, but was leaking from both muffs. Full water pressure. I did the job on a stand, and lowered the upper onto it carefully. I checked that the bottom of the tube was within the sleeve, and the coupler below it. I replaced and lubed both o- rings in the coupler too.
If the tube wasn't connected, wouldn't water spray out between the upper and lower housing? I didn't see that. Thanks

 

[alldodge]

Sure sounds like you missed it, or a hose was not put back on with a clamp.

Look inside the boat for a hose that came off, but there would also be water in the bilge.

The best way I found to put the two halves back together on a gen2 is, turn the upper have upside down, then flip the lower upside down and lower it in place.

Muffs spray water around the sides until the motor is running and then it slows down a bunch to just a small amount. The tube was putting some water thru the block but not full water. once the tube gets hot from all the exhaust gases and little water it can melt.

It could be something else but my bet is on the tube. Pull the drive and put some water into the top side hose connection and see if it runs out the prop hub. If it does the tube is not attached.

 

[alldodge]

Try this it should be easier, take the hose off going into the thermostat housing and put the hose on it going back to the drive. See if water comes put the prop hub

 

[StealthQ5]

The engine bay was dry afterwards. Your explanation makes sense - so it might have flowed for a bit and then melted, making the flow stop? Would there be any other damage (I ran it about 15 minutes)? Should there always be a healthy flow out of the lower gimbal housing? The muffs were spraying most of the time...

My concern when I placed the upper half (tube was in the upper) was how the tube was going to insert into the coupler o-ring properly. It becomes an act of faith at that point! I assume the upper hose connection you mention is the matching drive face hole that mates to the hole next to the gasket on the bell housing face (with the o-ring)?

 

[StealthQ5]

Thanks for your help AllDodge - it is greatly appreciated! I will try the easier method. Not good news if that tube came off, but it is what it is. But to repeat, there should always be good flow out the gimbal housing if things are working properly?

 

[alldodge]

Thanks . But to repeat, there should always be good flow out the gimbal housing if things are working properly?

You should always see water coming out the relief ports.

Just to clarify something for my self. There is nothing wrong with the water getting hotter, what I took away from the thread is the water stopped coming out the relief ports and was only coming out the prop hub. Was the water coming out the hub also hot? and do you have closed cooling?

If you have closed cooling with a heat exchanger then the 180 degrees is OK, but if you have pen cooling it is not

 

[StealthQ5]

I have raw water cooling only. There was no water coming out of the prop hub at any time. Also, I'm not sure I believe the gauge's 180F either because a couple of minutes after shutting down the engine, I opened the engine compartment and shot both risers with an IR gun, getting about 166 F...

 

[alldodge]

There was no water coming out of the prop hub at any time

OK now this is different. Water was coming out the reliefs and at no time was the water coming out of the prop hub. Then the water stopped from the relief ports and still no water out of the prop hub. The 166 degrees on the risers is OK for being on a hose.

Did the water just get shut off?

If there was a water tube connection disconnect the water should have been going out the prop hub. Now if the impeller chewed up then the hose would not be able to push the water thru the block. If the water pump is chewed up and you connect the hose to the thermostat hose, then water will come poring out the intake holes on the side of the drive and not out the prop hub

 

[StealthQ5]

Ok - now I've got my homework to do - with diagnostics via the hose. Thanks for that, since I don't yet have my brain wrapped around the complete engine/drive cooling system details. Glad I didn't take it on the water before doing this! By the way, the temp gauge was showing 180F last year on the water, which drove me to do this impeller change. It was the first one for this boat, and the impeller really looked pretty good...

 

[StealthQ5]

I think the only thing that could have happened to the impeller would have been a backward installation. I'm sure I rotated the drive shaft clockwise while pushing the impeller housing down on top of it. Or did I? And I used the one-piece OEM gasket along with alignment pins. I suppose a backwards impeller may have tried to rotate for a while...

 

[Rick Stephens]

Running on muffs, most of the water will leave through the relief ports and not the prop hub. This is particularly true if you have the drive trimmed up a bit. BTW: don't even start a Mercruiser without lowering the drive into a run trim position. Left up it puts enormous stress on the CV joint and will beat the u-joints out of itself.

I grabbed a pic off the internets of an old sterndrive running. Red arrow is pointing at the left side relief port. Idea behind those is that when idling, the exhaust exit down at the prop would create too much back-pressure for the engine to run. So there are exit holes higher up in the gimbal housing.

 

[StealthQ5]

If I need to remove the drive again to replace any parts per the above advice, do I need to use a new 1) bell housing gasket, 2) water passage o-ring, 3) quad seal between the upper and lower drive halves? It has been assembled for about a week, and run only on muffs as I said above...

BTW Rick, my drive only sputtered and drizzled water, it didn't flow out the relief ports as in the photo. My drive is always trimmed in when running or when parked...unlike nearly all the non-dealer boats I see on trailers... Thanks

 

[alldodge]

If the gaskets are not torn when removed you should be able to reuse. If you do have to get back into the drive it needs to be pressure tested before filled to ensure the seals are good.

my drive only sputtered and drizzled water

With this comment I do thing there is a pump problem

 

[StealthQ5]

If you do have to get back into the drive it needs to be pressure tested before filled to ensure the seals are good.

With this comment I do thing there is a pump problem

You may well be correct. I guess my chances of seal problems will increase if the water tube is found melted, so I'm hoping for the best with that. I looked for pressure testing in my Mercury Service Manual #14, but could not find it. I've seen many postings about pressure testing at the drain hole using everything from 5 to 15 psig, and even some who say it's unnecessary because Alpha One Gen IIs do not run pressurized. Any opinions about technique for this, pressure, time at pressure?

 

[alldodge]

In the link below the explains testing. Tester is screwed into the drain or vent hole with the drive empty. Needs to be able to hold the pressure for an hour or so and with the prop shaft and drive shaft manually rotated every now and then. Use a hand pump to pressurize and it needs a way of sealing off. Most use a shrader valve to seal off.

http://forums.iboats.com/forum/engi...ves/537689-od-presure-test?t=524743&p=5509236

 

[StealthQ5]

Thanks AllDodge - exactly the info I needed...

 

[StealthQ5]

OK, so I decided to go ahead and just pull the drive anyway (undrained as achris suggested in another thread - thank you!) because I wanted to see if there were any obvious obstructions or debris in the exhaust bellows or bell housing water port. I saw nothing in those areas. I then removed the raw water inlet hose from the thermostat housing, adapted a water hose to it, and turned it on full. At that point, I then got full flow out of the bell housing water inlet port, telling me there is no obstruction in that flow path. I then 1) looked into the water passage in the upper drive housing, and saw nothing, 2) looked at the water tube, and saw that it was inserted in the guide as it should be, and to the extent I could see it, appears to be intact.

Is there anything else that I could do, diagnostically at this point, before draining and separating the drive halves?

 

[Rick Stephens]

Hook the inlet hose back to the thermostat housing. Shove a cutoff end of a garden hose in the bell housing water inlet port and turn it on. There is nothing to stop the water from going through to the engine and out the exhaust. The tight fit of the impeller prevents water flow when attaching with muffs. With water hooked up this way you can even fire up the engine, no outdrive attached, and run it all you like, or at least until you are sure that it is getting sufficient flow and maintains proper temperature.