76 6hp cooling question

[hjalbert]

Hello, and thanks in advance for any help. This is a motor for a friends sail boat. Sat for about a year, lower unit oil is creamy looking. the picture will say the rest, I am curious if this is normal, or should water also be coming out at the top? Also, any Idea where the thermostat is? Thanks Again!

 

[Whoopbass]

Re: 76 6hp cooling question

Yes water should be coming out one of those holes at the top.
You better check the impeller and replace it regardless. Stick a how with a jet nozzle in the water tube after you drop the lower unit and you should get water coming out of one of those holes or else you have an obstruction.
You might want to check the t-stat as well (if it has one).

You most likely need to install a seal kit on the lower unit to stop the water intrusion. It could be just the nylon washers on the drain screws leaking but I doubt it.
However, I did run a 25 hp Johnson for years with a leaky lower unit. I just changed the oil a few times a season. When I did install a seal kit the gears still looked brand new so no harm was done running it on milky oil.

 

[Frank Acampora]

Re: 76 6hp cooling question

Before you go getting nervous, the water pump is up high, where the four mounting bolts for the lower unit are. This sometimes makes it difficult to prime with a hose and muffs. So first thing, try with the leg submerged and see if that improves the water flow. If not, then you certainly need to replace the impeller.

NOW: With creamy or milky lower oil, this indicates water intrusion. If free water did not drain out first, then the leak is not too bad. First check the fill and vent screws for tightness and gaskets. Then, check the prop shaft seal for leakage. finally, check the shift rod seal and the drive shaft seal. All seals are still available.

Since you will have the lower unit off to check some of these seals, I makes sense to replace the water pump impeller at this time.

If I remember correctly, that impeller is more expensive than the ones for the larger engines: About 26 bucks. But, It is still available. Try The Chrysler Crew and franzmarine@aol.com

 

[hjalbert]

Re: 76 6hp cooling question

Thank you both for your replies. Any Ideas about thermostat location? I pulled off the lower unit, the impeller is in good shape, but it is larger then the housing, in order to insert it in I have to twist it at the same time, to bend the "fins/blades". I put the motor in a bucket, but now realize that I did not submerge it above the pump. on top of that one of the stainless bolts holding the water pump housing on was seized and snapped. I need to get an ez out before Putting everything back together. Having never worked on a boat engine before I do not know if that is normal or not, any one know? I wonder if not then maybe they replaced it at some time with the wrong size? Or am I wondering to much. Drive shaft seal is good, or appears to be, on both sides of the impeller, the shift rod seal going up into the engine is loose fitting, more like a grommet. going into the lower unit it appears there is no seal, the shaft looks to be a machined fit, at least looking at it from the top. I have not disassembled the lower unit itself, other then to remove the water pump and the drive shaft. Thanks again! here is a a pic of the motor from underneath.

 

[Frank Acampora]

Re: 76 6hp cooling question

I don't know about that particular engine but on a lot of the snaller ones, the water pump bolt holes go all the way through the leg. So if that is the case and you can not get the broken bolt out, just take a punch and drive it out then use a longer bolt and nut.

I am reasonably certain the the upper "seal" is actually a guide to keep the shift rod from bending, because it is so long on the sailor model. There will definitely be a steel cased rubber seal where the shift rod enters the lower unit. It will be about 3/4 inch diameter. Chrysler and early Force used the same seal on ALL their engines.

Your water pump impeller is normal. Just be sure to bend the fins the correct way -- the engine turns clockwise looking from the top -- and do not reverse the impeller. The vanes will break-off.

Will check on the thermostat tomorrow. Not even sure those small engines had one.

 

[hjalbert]

Re: 76 6hp cooling question

thanks so much! by the way, my "friend" was doing her own homework and found this link, so I had to say shes awesome. John