Help required on old Mercury

[jonuk]

I decided to replace the water impellor on my blue band 50hp mercury outboard but after starting the engine up using a flushing device to provide the water to test it then after a few seconds black sludge mixed with the water started coming out of the centre of the prop so I stopped it immediately in case I had done something wrong in the rebuild.

The only thing I did notice when taking the lower unit off to get at the impellor was that a rubber seal dropped from somewhere and it looked like the top seal that goes on the top of the drive shaft but there was already a top seal on there so I presumed it had been mistakenly put in there at manufacture as according to the manual there are only 2 seals on top of the shaft which were there already ?

I did think that maybe because I had installed a new impellor that it had increased the pressure more than it was previously and that it was now flushing the oily deposits from the exhaust tube but there was also what looked like a lot of steam coming from the prop also that made me think it might be something else I had done wrong in the rebuild of the water pump ?

This is the first time the lower unit has been removed since I bought the outboard in 1979 as since then it has only done 30 or so hours running.

Any suggestions would be appreciated thanks.

Jon

 

[cannonford57]

Re: Help required on old Mercury

smell the black sludgy residue ,if it smells of gas(which i guess it will)its only excess fuel being dumped into the ex. housing washing the carbon down...remember,the engine hasn't been ran in a while much less brought up to temp....it should stop after a few mins.unless a carb is fllooding

 

[cannonford57]

Re: Help required on old Mercury

i gues you had a good stream of water from the tattletale hole.....right?

 

[billgabbert1]

Re: Help required on old Mercury

before you decided to replace the water pump was it not working? sounds to me like just some junk in the water passage. if you drop the lower unit again i fabed up a hose to hook up to the water tube on lower unit to make sure the pee hole was working. there should be no way any fluid should be in this passage.

 

[jonuk]

Re: Help required on old Mercury

Hi and thanks for the replies...

Problem of sludge now fixed as when I took the engine cover off I found the choke was stuck partially on and obviously running way too rich AND would you beleive I was running it on fuel that had been in the tank for the last 20 years ! ! ! ! ! ! !

Yeah I know it should be changed every 60 days but I just had to try it to see if the impellor was working and when the problem of the choke was solved it ran as sweet as you like on that old fuel that I presume was leaded being purchased 20 years ago.

It did start initially in the 4th pull but now I have put fresh fuel in the system its taking a lot more pulls to start than it did the first time but when warmed up it will now start with a quick short pull using about 6 inches of starting chord if that.

Got the choke working ok now but had to modify the choke lever as only the bottom carb was closing the flap fully but even so its still giving me shoulder ache starting it when its cold.

Only reason I got a manual start was it as purchsed new when I was a teenager and had to balance my finances between women and watersports but now 30 years later the women have won as they take it all ! ! !

Have ordered a pair of new diaphrams for the carbs ( without the wife knowing ) just in case they have gone hard but I am not too sure this is the problem as when its being started from cold then it will go first pull when warmed for 30 seconds or so.

Also I STILL have a spare top seal for the drive shaft that dropped onto the floor when I took the lower case off and have looked all over to see if that seal is used on another part of the unit but as I cannot find the seals listed on any of the online diagrams I am unable to see if its used anywhere else.

Once again thanks for your suggestions

Jon