Need help 94 Mercruiser 305

[Bry21317]

Re: Need help 94 Mercruiser 305

The water is now blowing out the Exhaust. The Temps are still running high though. I was going to do the clear hose test and the test to see how much water was flowing out of the input tube from the Lower Unit.

The temps are still running up around 175 and just over. This is with a 140 Stainless steel thermostat installed, with the correct O Ring and all new gaskets on the Thermostat Housing. I have a full water pump kit to install with all new gaskets, and including the SS Pump Housing. So if the tests fail, I will be installing this.

I had planned on doing these tests yesterday, but the problem is that it has been in the 40s and raining all weekend, still is raining now or I would be out there doing the test.

As soon as the rain lets up, I will be testing it.

Bryan

 

[Coors]

Re: Need help 94 Mercruiser 305

You changed what hoses to get water out the thru?
we need pics now.
something has changed.

 

[Bry21317]

Re: Need help 94 Mercruiser 305

The hoses were hooked up correctly. The problem, the mechanic told me was that one of the gaskets was not sealing all the way when he replaced the Impeller. So he fixed that. I still think there is a problem with the Impeller not pumping correctly.

I have not yet had a chance to do the Tests on the output of the Impeller. I was hoping to get these done this weekend, but it was cold and raining all weekend. It is still raining, but I am hoping that it will let up some tonight so that I can test it.

I will be hooking up a clear piece of hose to the hose that brings water from the impeller to the Thermostat housing to check for Air Bubbles. I will also then be testing to see what the output is of the impeller in 15 seconds as stated in the Mercruiser service manual. It should be 3.6 qts in the lake it states, so I am guessing it should be a little lower than this running off the hose. I will also put my finger over the hose to see how much water pressure it has as stated by another user on here.

I am dying to find out, but my guess is that the impeller is not pushing the correct amount of water to the engine. I have a full Impeller Kit with all the gaskets and the housing, ready to replace if this is what it seems to be.

Thanks for all the help, I will get it fixed with the help of you guys here.

Bryan

 

[Bry21317]

Re: Need help 94 Mercruiser 305

Ok,
So I finally got a chance to mess with the boat today as the rain quit for now. The hose that I got to test the Water supply at the thermostat housing was to small, and I got 1 inch diameter, so I decided to bite the bullet and drop the lower unit.

Well what I found is not making me happy. The water pump body did not have the Face seal installed on the Drive shaft above the pump housing. I am not sure if this would have caused any problems or not, but this was missing.

The next thing that I found was that 3 of the screws on the water pump housing were very loose, which would cause a big problem, I think. I think this would allow air to leak in, no matter what.

The third thing that I found was where the gasket mounts to the Lower unit body itself, it had alot of corrosion and did not have smooth surfaces.

I have not yet put it back together, as I need to know what type of sealent to use when the manual states to use the Quicksilver Perfect Seal.

I have sanded the surface that the gasket will lie on very smooth and got it all cleaned up. I also have the new Face Seal to install when I put the lower all back together. I also will tighten all the screws to the specific torque and use LocTite on them, to make sure they do not get loose.

One question I have is the Rubber Dam, that is installed, does that go with the Lip down, or with the lip facing up, towards the upper unit and water pump housing? This was installed with the lip down, so it was a flat surface under the water pump housing. I am unable to tell how this would go from the Mercruiser Service Manual.

Thanks for all the help guys, I am hoping this is the final problem that I need to get rid of for now at least, to kill the overheat problem.

Thanks,
Bryan

 

[Don S]

Re: Need help 94 Mercruiser 305

Way back on reply #5, I said the FIRST thing with an overheat you check is the impeller. Had you done that, this post would be over.
The other thing, had you looked at the link to the service manual on reply #20 that John S gave you, you would have had this thing fixed back together and working.
Not everything can be done on a forum. Eventually you have to get the book and go to work and WORK on it.

 

[Bry21317]

Re: Need help 94 Mercruiser 305

Don,
I trusted that the mechanic had done as he stated. Well I was wrong. Never trust anything that is done, by a shade tree mechanic.

I trust your judgement. I will listen for sure from now on, the mechanic had the boat for a while and I got it back last Thursday, and Will not be taking my boat anywhere. I will do all the work myself, from now on for sure. Just thought that since I had not done the impeller on this drive, it would be done right, by letting someone else do it.

I have the Mercruiser Manual that was given to me in Post 20, I printed it outand put it in a notebook. I have read through about the whole manual, as I like to learn about the engine that I have. I have looked through it, and it does not show the way that rubber dam goes in. Can you answer that question for me. Also can you tell me what to use for the Perfect Seal?

Bryan

 

[Don S]

Re: Need help 94 Mercruiser 305

Never trust anything that is done, by a shade tree mechanic.

Personally, I would never take anything to a shadetree mechanic.

Just thought that since I had not done the impeller on this drive, it would be done right, by letting someone else do it.

Wrong assumption if you were taking it to a shade tree mechanic.

Look at page 3B-78 of the manual for the dam information

 

[JustJason]

Re: Need help 94 Mercruiser 305

I believe there are 2 M's in damm... Donn

 

[Don S]

Re: Need help 94 Mercruiser 305

I believe there are 2 M's in damm... Donn

Not exactly, it would be DamN not 2 m's, but that is not the kind of damn I meant.
I was referring to the RUBBER DAM in the drive.

 

[Bry21317]

Re: Need help 94 Mercruiser 305

I thought the guy new what he was doing, but I was wrong. It seems for sure.

So anyways, I have looked at this picture in the Manual 3b-78. From the Picture it looks like the Lip on the Dam is facing upwards. So this would leave a gap where the weep hole on the water pump gasket could drip water. Am I correct on this?

Also, I noticed that when I dropped the Lower unit, there is Lower unit oil leaking out of the hole in the casing, which I know should happen, but it is also leaking where the drive shaft goes up into the upper. I don't think this is correct, but I am not sure. Should it leak here or no?

Bryan

 

[JustJason]

Re: Need help 94 Mercruiser 305

Not exactly, it would be DamN not 2 m's, but that is not the kind of damn I meant.
I was referring to the RUBBER DAM in the drive.

Such a cunning linguist Don... I really thought you meant it the other way!!

ps~how many posts does it take to get to the center of a water pump??!?



Main Entry: dou?ble en?ten?dre
Pronunciation: \ˈd?b-əl-?ⁿ-ˈt?ⁿd(-rə); ˈdə-bəl-?n-ˈt?nd(-rə)\
Function: noun
Inflected Form(s): plural double entendres \same also -ˈt?ⁿz; -ˈt?n-drəz\
Etymology: obsolete French, literally, double meaning
Date: 1673
1 : ambiguity of meaning arising from language that lends itself to more than one interpretation
2 : a word or expression capable of two interpretations with one usually risqu?

 

[JustJason]

Re: Need help 94 Mercruiser 305

Also, I noticed that when I dropped the Lower unit, there is Lower unit oil leaking out of the hole in the casing, which I know should happen, but it is also leaking where the drive shaft goes up into the upper. I don't think this is correct, but I am not sure. Should it leak here or no?

Well... you need to put your thumb over the oil transfer port and put a couple psi in the upper and see what happens.....

 

[Bry21317]

Re: Need help 94 Mercruiser 305

Capt Jason,
Can you tell me where I would put the pump to pressure test this?

I will do so, I am getting to the middle of this thing. No matter what. Sorry to be such as pain in the A**, but I should have just done it myself from the start, then I would have known it was done right the first time, and not had all these problems.

Bryan

 

[JustJason]

Re: Need help 94 Mercruiser 305

vent screw

 

[Bry21317]

Re: Need help 94 Mercruiser 305

Gotcha, would the Lower unit oil pump work for this?

Just wondering.

Bryan

 

[JustJason]

Re: Need help 94 Mercruiser 305

you need to pressureize the drive with compressed air... not pump oil into it.... see if it holds.... oh off the top of my head i think its around 8psi... but ya may want to double check that.
you need to read that manual some more dude.

 

[Bry21317]

Re: Need help 94 Mercruiser 305

Gotcha,

Been reading it all day here at work.

Thanks,
Bryan

 

[Coors]

Re: Need help 94 Mercruiser 305

I have sanded the surface that the gasket will lie on very smooth and got it all cleaned up.

I hope you used a straight edge. Get a coarse rasp and run across it to check for it being flat.

 

[Bry21317]

Re: Need help 94 Mercruiser 305

I have checked it and it is flat. I did not sand that much off of it, it was not that bad. Just got the some light build up off of it.

Also, I just pulled the Top cap on the Upper unit. I found where the oil was coming from. The piece ( I am guessing coupler) that the lower unit drive shaft slides up into. When I removed the top, I found there is a hole in the middle of this drive shaft in the upper, as I can see right through it, when I look down through the shaft I can see the ground. This is where the oil is leaking down and out, with the lower removed. This hole loooks that it is supposed to be there. There is a hole in the middle of my lower unit drive shaft also, but it only goes down about 1/8-1/4 of and inch. So when this is in place, it should not leak. This is where the top bearing is located, that has its race in the top cap on the Upper. I replaced the Oring around the Top cap also. So now I just need to wait till I get one more part, which will be here tomorrow and then I will give it a shot, and see how she runs, but its supposed to start raining again for a few days.


Bryan

 

[MikDee]

Re: Need help 94 Mercruiser 305

Well Bry it looks like you have all the best people, & best advice, so far but I just want to mention one item to check, and I think it's been mentioned before. It is the 1" seawater hose that goes from the lower unit, into the bellhousing, then thru the hull plate to feed the motor, it has a bend in it to conform to the tilt angle under the bell housing, it has a tendency to dry out, & crimp some at that point, blocking circulation somewhat, I had this happen to me, if you check it out the hose is a recommended Mercruiser part, (not sure if the manufacturer matters?) But, it does have a certain precise mercruiser measurement it needs to be cut to in order to work properly.

I cheated, and took the hose off, and slipped a snug, form fitting, 1-1/4" -
45* copper elbow over the 1" hose using some soap, then slipped the hose back on, and it kept it at just the right angle, without letting the hose crimp, it worked just perfectly from then on!