Merc 7.5 mid 60's Hot lower unit

[rookiedave]

Hi, 1st time boat owner. Could only afford a little used motor and everybody says that these little motors are great. I rebuilt the waterpump most of it was missing and installed a new impeller the way that was told on this forum.
Put it all back together and placed it into bbl. pulled start cord and after few pulls started. Lever on the starbord side is all the way to the aft position motor coughed and started. as soon as i could turn choke, the motor jumped into a very high roar and threw most water out of 55 gal drum. water was coming out steady in a stream from the tell tail and did not feel very hot to me. after few seconds i hit stop button. all down shaft towards prop was very warm to hot for so little time running. did i do something wrong with the water pump. i smelled a slight burning smell and saw some light smoke. Normal for a 2 stroke? I do not know how many decades the guy had this thing on his shelf. It was his dads motor he said. I welcome any advice. I really do not know the proper way to start this little motor....but it really seemed strong while it was dumping 55 gallons of water all over my garage floor!!!!! Obviously I do not have a owners manuel for my motor. I watched the same motors on youtube but they did not really go into detail on starting.
thank you
dave

 

[ss von scalliwag]

Re: Merc 7.5 mid 60's Hot lower unit

Hi Dave,

I have found that the best way to start these it buy giving it a LITTLE bit of throttle (about 1/8 turn past start position) and puting the choke on full. Pull the start cord and as soon as she fires turn the choke off completly and return the throttle back to the start position and let it warm up on idle for a couple of minutes before you set off.
A quick test to see if you done the water pump properly is that when its running you should be able to place your hand on the block without getting burnt. The block should stay nice and cool (unless its under load at WOT:redface.
Good luck and let us know how you get on.

 

[rookiedave]

Re: Merc 7.5 mid 60's Hot lower unit

Thank you. I will do as you said. I have ordered a new impeller since it has been brought to my attention that I did not install it properly. The parts person gave me the wrong gasket...who knew!!!! So after I pull the lower section again I will post and let you know if it worked....
I would really like to thank you for your help. I do apreciate it more than I can say. I always wanted to "get in" to the boating lifestyle and I really can not afford much better at this time so I must make do....for now.

 

[rookiedave]

Re: Merc 7.5 mid 60's Hot lower unit

Hi,

Just put my 2nd impeller in today. This time it went in so much better. I fired it up and it ran great. A little smokie but it sounded very strong and ran a long time 10 min before I shut it down. I ran it at idle and at fast rmp. it did not even skip one time. Took the cover off and touched the "block" a little warm but not scalding. Only question is the pee hole does not have more than a trickle of water coming out of it. This time I know, that the impeller is installed correctly. What should I do next?
Thankx
dave