72 johnson 100 impeller faith.

[jamminmaz]

Good afternoon,<br />I have a 100ESL72R motor. I have had it on the lake 3 times and it runs great. There are two holes on the back of the motor just about waterline level. I thought this is where the cooling water was supposed to squirt out, but even 30 minutes on the lake there is only a slight oozing of hot water out of these holes at idle speed. I hooked up to the muffs and ran it for a minute and noticed alot water squrting out of a few holes down in the lower unit. The water coming out was warm which tells me it was going through the motor. The water would squirt out of these holes just from the pressure of the hose water, so I cannot tell if my impeller was pumping this water, or if it was just the pressure of the hose? Is there a better way to tell if i need to replace the impeller? I dont want to burn up the motor, but dont want to take apart if i dont NEED to ya know?<br /><br />Thank you very much

 

[BF]

Re: 72 johnson 100 impeller faith.

unless you KNOW the impeller has been changed in the last couple of years, I'd change it even it seems to be working OK now. Chances are even if someone says it was changed "a couple" years ago, it often means 10+ years ago. I've changed impellers that I thought probably weren't bad, and then saw the much larger volume of water the new ones pumped and then knew that the old one was overdue for replacement. Replace even if the old one "looks" ok, they can look fine, but not pump very well.<br /><br />on preachy soapbox:<br /><br />owning an outboard means that there is some technical knowledge required (like knowing about mixing fuel) and some regular maintenance needed (e.g. spark plugs, lower unit lube, impeller). It's not hard to do yourself, or you can pay someone to do the maintenance, but if you want to avoid problems in the longer run, it needs to be done.<br /><br />off preachy soapbox: <br /><br />the impeller job probably won't be as bad as you think it will be.<br /><br />hope this helps...<br /><br />Brent

 

[Xcusme]

Re: 72 johnson 100 impeller faith.

Jamminmaz,<br />Since you havn't mentioned if this is a 'new to you' motor, i'll guess that you don't know the last time the water pump(and possibly the thermostat) was replaced. If you can't tell if the motor is cooling naturally (good water pump), my advice is to replace the waterpump. Even if you can touch the powerhead a few seconds without burning youself, you still won't have a clue as to when the pump will leave you stranded, or worse yet, an overheated motor with major damage. You will eventually, at some point in time, have to replace the water pump,why not now? You will then know for sure that it's working and have piece of mind. Is the motor worth $50-75 bucks and a couple of hours of your time?? That's the cost of a service manual and replacement parts.

 

[ledgefinder]

Re: 72 johnson 100 impeller faith.

That motor doesn't have a water 'telltale' like the newer ones. <br /><br />Those two holes in the back are exhaust reliefs. Once the motor is warmed up, you should get a little mist there at idle, and a heavier 'rain' during high-throttle operation. You may get no mist at all there when the motor is cold.<br /><br />You should have a hot horn (it's in your control box). Some of the older one's just have a hot light. You can check it's operation (and should) by finding the temp sensor. It's on the starboard head. There is a connector in the wire about a foot from the sensor. Slide back the rubber sleeve, and ground the connnection to the block. You should then hear the horn.<br /><br />There's no way to judge the condition of the impeller without pulling it. The one on that motor is fairly well designed (particularly relative to that in, say, the 40-70hp Merc lower unit), and plenty of people run them for years & years (ignorantly) without trouble. But, you are taking a chance; if the hot horn doesn't alert you to trouble you're first indication will be when the motor $ieze$ up...

 

[jamminmaz]

Re: 72 johnson 100 impeller faith.

Thank you all for the quick and detailed responses, I really appreciate it!<br /><br />I will change the impeller jut to be safe, then and while I am in there change the lube also. Should I do the T-stat too? I have heard several different replies as to what kind of lube to use on ye ol' hydro-electric. Does anyone know for SURE? I will get the shop manual ASAP!!<br /><br />Thanks again.

 

[Dhadley]

Re: 72 johnson 100 impeller faith.

Change the complete pump kit, not just the impeller.<br /><br />Good luck!