50 Hp 4 stroke Tracker Low water pressure

[Proline17]

Wanted to post our experience.<br /><br />1995 Four Stroke Mercury 50 HP<br /><br />For some time now the water pressure guage had been reading very low.<br /><br />The people at the marina replaced the water pump but had no idea why it was still low on water pressure and recommended we send it back to Mercury ! LOL<br /><br />Since it has a waterhose all of the way up to the guage, we checked it first. It was OK.<br /><br />Next we replaced the waterpump - with no effect.<br />Next we replaced the thermostat - with no effect.<br /><br />We felt like there had to be a restriction somewhere.<br /><br />So off went the power head to inspect the water tube that runs between the pump and the bottom of the power head. At the top of the tube is a rubber grommet.<br /><br />Sure enough - the metal surrounding the rubber grommet under the power head corroded and expanded and constricted the grommet. The grommet had been restricted to less than a quarter of an inch!<br /><br />We went to Gulf Coast Marine in Homosassa where they had all of the gaskets in stock...unlike the place where we bought the boat (name witheld)<br /><br />In talking to the guy there he says it's a VERY common problem on those engines and changes the grommets quite often.<br /><br /><br />I hope this helps someone someday.

 

[BillP]

Re: 50 Hp 4 stroke Tracker Low water pressure

Hey Proline 17,<br />I have a 1996 50 Mariner (merc) 4 stroke and my local dealer told me this was a common happening too. I've been lucky but attribute that only to flushing every time I use it. <br /><br />Has your motor been flushed every time after saltwater use? Or being from Crystal River, is it a fresh water motor? <br /><br />If the grommet was squeezed by tube corrosion did you replace the tube or just dress it and put a new grommet in? How much labor to take the head off?

 

[Proline17]

Re: 50 Hp 4 stroke Tracker Low water pressure

The boat is a 21' pontoon that has always been used in the gulf and stored at a marina on the Homosassa. The only flushing it has ever received has been the trip up river on the way back.......needless to say they're not much on maintenance.<br /><br />The tube was not corroded. It was the "powerhead to driveshaft housing adapter". In short, it's what the powerhead bolts to. It has a hole which the grommet and tube fit into. It MUST be removed from the top thus requiring the removal of the powerhead. After the side covers are off there are only 8 bolts. No problem.<br /><br />Also, there was a 3/16 hole that burned through the outside from an exaust passage on the port side. Have you heard of others doing this?<br />We put some JB weld while the powerhead was off. Only time will tell.