Water Pump Woes

[Moody Blue]

1992 40HP Mariner 4 cyl. Searched the forums but havn't found any relavent info. Hoping someone can offer some assistance. <br />Problem 1)After removing the lower unit I noticed that the water pump housing is not separated/protected from the exhaust tube. Is this normal ? Parts dwgs online show some kind of rectangular shaped seal and collar as part of the lower unit that my motor doesn't seem to have. Is it missing or is this normal ? There is no sign of any damage or distortion from heat.<br />Problem 2) My Clymers manual refers to an o-ring on the drive shaft. The water pump repair kit came with an o-ring about 3/4" dia but one was not found when I removed the lower unit. There is a slight groove on the drive shaft just below the top splined section. Does an o-ring go there ?<br />Thanks for any help.

 

[Laddies]

Re: Water Pump Woes

Newer engines don't use the o ring on the driveshaft, but the older engines like yours do

 

[Moody Blue]

Re: Water Pump Woes

Thanks laddieservice, where does it install ? Is it possible the old one is stuck in the power head ? Any thoughts on the exhaust tube ?

 

[Scali]

Re: Water Pump Woes

I just changed impeller & WP gaskets 1994 40.<br />The Seloc manual showed a rubber washer thing/coller under the top spline that seats in the crank.<br />Went to Merc oredered one $ 9 part & it didnt fit.<br />Some have them some dont, if you pull the LU every couple years it wont matter ..<br />You do want the rubber slinger that snugs up to WP on the driveshaft though.<br />As far a WP housing / exhaust tube thing, maybe it's stuck in the upper housing.<br />It slides down from upper housing & seats in LU on rubber seal thing

 

[Moody Blue]

Re: Water Pump Woes

Now I understand the o-ring, thanks. This motor though does not have a separate removable exhaust tube. Looking up into the leg I can see a round 2-3" exhaust port from the power head. It simply opens into the leg where the driveshaft, shift shaft and water tube are housed as well. Seems pretty clean in there but it has me worried that the exhaust gasses are not channeled down to the lower unit. Can anyone offer an explanation ?

 

[KCLOST]

Re: Water Pump Woes

Normal, The exhaust will exit down to the lower unit at higher rpms when the water is also allowed to exit via speed vaccum pressure. At idle the exhaust will only exit the upper exhaust port(s)...

 

[Moody Blue]

Re: Water Pump Woes

OK I feel somewhat better. Afterall this motor has run for years as is but I still wonder why a separate exhaust tube is shown in all the on-line parts listings like mercuryexpress and dougrussel. Are they generic drawings for different motors ? I know this sounds like a trivial concern but I hate to have things not work as they were intended. Thanks for your help.

 

[Moody Blue]

Re: Water Pump Woes

bump

 

[rodbolt]

Re: Water Pump Woes

the exhast tube is pressed loosly on the exhaust plate and loads in from the top under the power head. no seas to it. some of the early 4cyl motors had a seal but not by 92. we did have plenty of upper mount failures on those motors I got it down to an hour or so job if the corrosion was not bad.

 

[Moody Blue]

Re: Water Pump Woes

Can I run the motor without the exhaust tube ? Looks like it has been without one for some time. What do you mean by upper mount failures ? Something I should be on the lookout for ?