1976 Mercury 650 running after 4 years but now having control issues!!

General0

Cadet
Joined
Jul 5, 2006
Messages
19
I just had to give a bit of praise to the durability of this engine!! I bought this boat and motor back in 2005 and never started it even then because of the work needed on the transom and floor. The boat is done now and I want to move on to the motor now.

I verified all the connectors were seated and the only problem I'm having now is the controls for the forward, neutral, and reverse are extremely hard to move back and forth. I was able to put it into neutral with a little coaxing though.

I placed the muffles on it and turned the water on and then I turned the engine over. After about 3-5 seconds of cranking low and behold it roars to life!!! I was a little shocked buy this so I immediately turned it off, but again I cranked it for about 3-5 seconds and it roared to life, but it was idled a little high, once it cooled down it just purred! I left it running till the gas was empty and about the only thing I did notice was a leak in one of the hardened rubber lines.

I know I maybe should have done a few thing to this motor before I went cranking on it and starting it up after that much time sitting on my garage floor so can anyone give me any idea what I should do before starting it back up or taking it out to the lake and why is the shifter is so hard to move? I have no binding in the lines and there is no rust that I can see and it moves freely when not connected to the engine also.

Sorry about the long post btw.
 

Yachtzee

Seaman
Joined
Oct 13, 2007
Messages
72
Re: 1976 Mercury 650 running after 4 years but now having control issues!!

I have awakened three of these motors.
A couple of things. Running on Muffs does not always equate to running well on the water! They can run like crazy on muffs and can't get out of their own way out on the lake.
Is it "peeing" from the telltale as it should? Even if it does. . .
You absolutely need a water pump impeller.

You may need a fuel pump kit(s)

I'd run some Sea Foam through it and give it the Deep Creep treatment that you can find in the archives here.

I'd also drain and replace the lube in the lower unit.
Any number of things could make it hard to move the lever. Bad cables corosion in the control box of a some unplesaant thing in the lower unit. Again change the gear lube first.
 

General0

Cadet
Joined
Jul 5, 2006
Messages
19
Re: 1976 Mercury 650 running after 4 years but now having control issues!!

great thanks for the advice, I have read every post I could find on this engine so I agree with you dead on about the things I should check. I'll post a update if I can get it in the water after fixing these few things. I did find a water pump/impeller kit I had in a box that was given to me when I bought the boat, would this be ok to use with it being so old?
 

prolinews

Petty Officer 2nd Class
Joined
Feb 1, 2005
Messages
165
Re: 1976 Mercury 650 running after 4 years but now having control issues!!

cables most likely the culprit. When Disconnected There should be almost zero effort in shifting. Most controls have a tension screw check it might be cranked down all the way I doubt it but check it. If cables check out hooked up to the shifter try manually shifting might be a grease issue in slide . If that checks out disconnect cables in shifter and check shifter while cables are disconnected from both shifter and motor try them once again almost zero effort on a good cable. If it were mine I give it a super tune up new plugs carb kits rebuild fuel pump new hoses, and lines water pump ( the full kit housing plates impeller tube etc.) check all wiring mercs are bad for rotting wires and new control cables. For less than 200 bucks you will be zipping across the water in no time. good luck!
 
Joined
Sep 5, 2007
Messages
1,790
Re: 1976 Mercury 650 running after 4 years but now having control issues!!

I agree 100% that you need new fuel lines and carbs cleaned. Grease to everything that slides too and dont forget to put in new plugs..You will be bustin the wake soon.
 

General0

Cadet
Joined
Jul 5, 2006
Messages
19
Re: 1976 Mercury 650 running after 4 years but now having control issues!!

Hey, thanks for everyone's replies. The cables are all working fine, I ran the engine in a tub of water and it all of a sudden now shifts just fine?

I have looked around my town but no one will touch my motor,they say it's too old? Does anyone have a idea of who I could go to in Minnesota (Minneapolis/Saint Paul area) to get it serviced?
 

scottkborchardt

Recruit
Joined
Sep 18, 2009
Messages
2
Re: 1976 Mercury 650 running after 4 years but now having control issues!!

While searching for an impeller for my 1976 Mercury 650 3 cyl., I was happy to learn that you are having good results so far. I just bought my 650 and boat/trailer in as is condition for $750 and was wondering if the motor was any good. The man at the Mercury Dealership here where I live said, in his opinion, the 3 cyl. 650 was the worst motor he has ever come across in 20 plus years of working on boat motors. The motor has no cylinder head and was manufactured to save the cost of a head but small cracks in the combustion chamber usually develope and push air/fuel into a water jacket that is on the outside of the motor around the spark plugs. He said some customers of his have said that it looked like the plugs were leaking water .
He said the 70's were live it up times and Mercury's Engineers cut corners to get a motor to the demand. He said if my 650 was a good one, it would be the first one he has seen. They usually do not get the full life expected he added.
I am still out to fix this one up to see what it will do. To my suprise I had mine start the other day but fried the impeller before I could shut it off. It ran about 3 minutes and I pulled the fuel line to kill it. Is yours a 3 or 4 cyl.? Have you heard bad things about the 3 like this? Scott
 

RaScLeS

Petty Officer 1st Class
Joined
Jun 27, 2009
Messages
230
Re: 1976 Mercury 650 running after 4 years but now having control issues!!

3cyl mercs have a bad rep from what ive seen. I cant even get mine to run on all 3 and parts are so expensive
 

scottkborchardt

Recruit
Joined
Sep 18, 2009
Messages
2
Re: 1976 Mercury 650 running after 4 years but now having control issues!!

Thanks for the reply. Any additional info. on the 1976 Mercury 650 3 cyl. will be appreciated. Scott
 
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