need some expertise on 50HP merc

[hankster]

I just bought a 1987 Smoker Craft and it has a 50HP Merc that says oil injection on the side, and I assume its the same year. The guy I bought it from took the injection pump off and I just have to mix it 50:1 manually. I took it out today and it runs great but I did notice a couple of things; the motor makes a wierd noise(hard to explain) at all rpms, almost sounds like an exhaust leak but more of a squeaking. Also, the water does not come out of the port on the back, it kinda leaks out just below from the two retangular port holes that I think are for exhaust. He told me that this engine has a thermostat and it wont come out of the rubber tube until it warms up. Well It ran for a good hour today and never came out of there.

I guess my question is, could it be a bad pump or impeller making the noise and not shooting water through the tube?

Sorry for the long explanation and thanks in advance for any help!

 

[verado7]

Re: need some expertise on 50HP merc

could be all of the above - not sure if the fifty has t-stats though - at any rate dont run it until you correct the problem and hopefully the seller didn't run it hot either - change the water pump anyways and if applicable the t-stats - not all engines have them .

 

[spemux]

Re: need some expertise on 50HP merc

Hi
I'm a Mercury Technician from Europe;
Change the water pump (includes impeller, gaskets and other necessary parts comes with the box) and test it. If you don't want to spend money, just change the impeller and make sure gaskets are ok. If water is still hot, change the thermostat.
If there is no water coming out, check all the water hoses going to block thermostat etc. Use a compressor or blow it with your mouth and see if the hose is ok.

And let me know about the impellers condition.
It happens pretty often.

Excuse my English skills.

 

[hankster]

Re: need some expertise on 50HP merc

Thanks for the quick reply. Is the water pump/ impeller in the lower unit? I have been searching some treads and kinda confused. From what I have read, I can drop the lower gear case and the pump/impeller is right there.

 

[spemux]

Re: need some expertise on 50HP merc

Thanks for the quick reply. Is the water pump/ impeller in the lower unit? I have been searching some treads and kinda confused. From what I have read, I can drop the lower gear case and the pump/impeller is right there.

Hi again
Yes, water pump is in the lower unit. Split the lower unit from the engine.

Check the picture below ps. ask me anything you need to know. If you are doing it first time it can be pain in the butt.

 

[hankster]

Re: need some expertise on 50HP merc

Thanks, so the pump is in the lower unit? I am a first timer with outboards. Do you recommend I buy an entire pump or just an impeller, I guess I should get the old one apart and then worry about that stuff.

 

[Sandhammaren05]

Re: need some expertise on 50HP merc

spemux is holding the pump housing in his hand (the white plastic object). You'll have to reseal the housing correctly after removing it. And the gearshift rod must be unbolted from the powerhead before the gearcase will drop down.

If the impeller housing's smooth inside you need no more than an impeller. While you're at it, check the gear grease color. Whitish indicates water, bad seals oon propshaft and/or driveshaft. I always replace driveshaft seals when replacing a bad waterpump. So, you need a Mercury repair manual. You might find one on Ebay, I don't like Seloc manuals.

Thanks, so the pump is in the lower unit? I am a first timer with outboards. Do you recommend I buy an entire pump or just an impeller, I guess I should get the old one apart and then worry about that stuff.

 

[Mdub]

Re: need some expertise on 50HP merc

Here is a link to a good video on changing the impeller. I just did one on a 75 hp merc and it turned out to be pretty simple.
http://www.youtube.com/watch?v=E-uzQi7IgwU
You might as well get the rebuild kit and do it all while you are in there, they run about 40 bucks.

 

[hankster]

Re: need some expertise on 50HP merc

Thanks, got it off, piece of cake, now I am going to buy the new one. The only problem is that I forgot to see which ways the fins go when I took out the old impeller. All the housings look great and the impeller just has one small crack. Does it matter which way I install the new one? Also, never did find any t-stat, the manual I looked at in the library didnt have 3cyl merc 50 in it.
THanks

 

[hankster]

Re: need some expertise on 50HP merc

Thanks for everybody's help, I got the new impeller on and lower unit back up and still had no water coming from the pee hole. I pulled the tube coming from the block and the rubber 90 off and they were all full of crud, I assume some spiders or bugs made a nest. Cleaned it all out and it works awesome!

I still have a noise coming from the top of the engine while its running, almost sounds like the top flywheel is hitting something internally. I looked underneath it and looks like there is some kind of rotor or magneto that runs against it. Is it possible that something is worn and causing a noise? Doesnt seem to effect the engines performance so no sure if I should worry about it or get brave and pull the top flywheel off.

 

[Sandhammaren05]

Re: need some expertise on 50HP merc

Can't be because of wear, something must be broken or loose. Can be that the stator's loose and dragging against the flywheel, can be that the flywheel's loose. Don't run it further until repaired! How much lateral play is there in the flywheel?

Thanks for everybody's help, I got the new impeller on and lower unit back up and still had no water coming from the pee hole. I pulled the tube coming from the block and the rubber 90 off and they were all full of crud, I assume some spiders or bugs made a nest. Cleaned it all out and it works awesome!

I still have a noise coming from the top of the engine while its running, almost sounds like the top flywheel is hitting something internally. I looked underneath it and looks like there is some kind of rotor or magneto that runs against it. Is it possible that something is worn and causing a noise? Doesnt seem to effect the engines performance so no sure if I should worry about it or get brave and pull the top flywheel off.