Given an old Merc 500 HELP!!!

[Ap904]

First off I basically have no knowledge/experience with marine motors. I have worked on cars so I'm not completely lost on the concept. Someone recently gave a old boat with a Merc 500 on it. Supposedly the motor went thru an overhaul about a year ago and has been sitting since then. All I know about the motor is that it is a Merc 500 4 stroke 50hp. I hooked up the muff and a battery and got it to start. With full "choke" on I let it run for a bit. When I pulled back on the choke lever it sputtered a for a minute then died. Is this normal? I was hesitant to keep it running and trying because I noticed there was no water coming out of a pee hole (which I can't figure out exactly where that is supposed to be). There was water coming out of the exhaust and two small holes a little higher on the unit. I took the lower unit apart and pulled the water pump out and noticed broken pieces of plastic. The impeller and everything else looked fine (to my untrained eye). Thinking this was the problem I put it back together and still no pee. I have searched and searched for an answer but with no luck. There is a hole where I think the pee hole should be based on videos I've watched but no hose hooked up to it. Also there is a weird cut hose with screws in the ends. See photos. I have no idea what year this thing is and I'm extremely frustrated. I want to get this thing on the water but reluctant to cause more damage to the motor. What should I do?!?!

 

[Ap904]

 

[Ap904]

Sorry for the bad pictures. Thanks in advance!

 

[GA_Boater]

Some Merc don't have tell-tells. It may have a port built into the lower cowl about where the circle in the pic below.




On the plugged hose. I believe the the hose ends should be connected. The hose is either the bleed or balance hose - I forget which is which. There should be two similar looking ones on that side.

 

[racerone]

It is NOT a 4 stroke motor.---Hopefully you are mixing gas and oil at 50:1 on it.----It is a 4 cylinder , yes.

 

[Ap904]

Some Merc don't have tell-tells. It may have a port built into the lower cowl about where the circle in the pic below.






On the plugged hose. I believe the the hose ends should be connected. The hose is either the bleed or balance hose - I forget which is which. There should be two similar looking ones on that side.

So I should connect the cut hose? There is a hole by where you have circled in the picture but no water comes out and no hose connected to it? Thanks a lot for response and info.

 

[Ap904]

It is NOT a 4 stroke motor.---Hopefully you are mixing gas and oil at 50:1 on it.----It is a 4 cylinder , yes.

Goes to show what I know. I ran it for no more than a few minutes on straight gas....hopefully didn't totally damage the motor...thanks for letting me know.

 

[racerone]

The cowling and red stripes clearly indicate a 1969 model or thereabouts.

 

[Ap904]

So just to clarify - no pee with muff isn't something I should be concerned about?

 

[60sboater]

You may have scuffed your cylinders,or worse,depending on how long it ran.


It needs a 50 to 1 (50:1) gas to oil ratio of a good quality marine 2 cycle oil. It must be pumping some water to see it in the exhaust smoke. Where does the cut hose connect to on the engine? The broken pieces of plastic may be from the impeller although you say it looks good.

There's a site for old Merc enthusiasts called JohnsOldMercurySite.com you can join...small fee. You have to pay to get to the tech section. The old 50 is a well-loved engine and many have them. This site is good too but the other specializes in older stuff.

 

[60sboater]

Edit: Your 50 has exhaust through the hub of the prop and I don't recall if water should be present in the exhaust smoke where you saw it. I was running my '73 9.8 recently in a barrel and don't recall seeing any in the smoke. I think my old Mark 10 would have water in the exhaust below the power head.

 

[racerone]

Water will / should pour out with exhaust through the prop !!------Some will spit out with exhaust at the exhaust relief too.

 

[Ap904]

You may have scuffed your cylinders,or worse,depending on how long it ran.


It needs a 50 to 1 (50:1) gas to oil ratio of a good quality marine 2 cycle oil. It must be pumping some water to see it in the exhaust smoke. Where does the cut hose connect to on the engine? The broken pieces of plastic may be from the impeller although you say it looks good.

There's a site for old Merc enthusiasts called JohnsOldMercurySite.com you can join...small fee. You have to pay to get to the tech section. The old 50 is a well-loved engine and many have them. This site is good too but the other specializes in older stuff.

Not sure what it's attached to but there are screws in it like it was an intentional blockage. Hope these pics help.








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[Ap904]

Water will / should pour out with exhaust through the prop !!------Some will spit out with exhaust at the exhaust relief too.

Thanks for the info. So this motor is pre tell tale? I'm going to put it in the water tomorrow and see how it acts.

 

[60sboater]

Not sure if it's supposed to have a tell tale. What is the s.n. ... look on transom bracket face or sides for an i.d. plate. Maybe shoot some oil/fuel/WD 40 in the cyls before cranking to replace a protective film on the walls.

 

[turtles11756]

serial # tells year of motor post it. the hose that has been cut and blocked needs to be replaced it runs unused fuel/oil back to cylinders. your motor definitely has a tell tale water pump outlet should be right there under and back a little from the hose that was cut.probably clogged or disconnected by some idiot. get your self a mercury outboard service manual and learn what your doing you are probably fooling with a real good old merc

 

[Ap904]

Got the engine started today and let it run awhile with 50:1 but i noticed the motor is smoking. bad sign? Also the engine block is impossible to touch due to heat. It does die when I pull the choke lever back to 0 too.

 

[Ap904]

Not sure if it's supposed to have a tell tale. What is the s.n. ... look on transom bracket face or sides for an i.d. plate. Maybe shoot some oil/fuel/WD 40 in the cyls before cranking to replace a protective film on the walls.

1440-1333

 

[60sboater]

Smoke is normal but the block should not get too hot to touch. It's also too lean because of needing choke all the time...dirty cabs(s) and/or air leaks. I haven't seen a sn like that.

 

[racerone]

???------When the motor left the factory it had a telltale.--------If it is not working it is plugged or disconnected.-----Up to you to sort this out.