1973 Mercury 650 Nightmare

[jlconrad24]

I got this 1973 Beau Jack T169 a few months back. Started and ran great on the muffs. In the water in starts every time and runs great just scooting around, but if I go to plane off toward full throttle it dies, unless I can get it back into neutral in time. It has a new tank, bulb, lines, spark plugs, and just put a pump kit in it. Seems to sustain higher rpm longer now, but still results in a dead motor that will start back as soon as I hit the key??? The thing that has me stumped to pulling my hair out is the stinking lower unit. When I first put it in the water the reverse lock did not work. Someone gave me the tip that the cam was out of line from a recently installed water pump. Dropped the lower unit for the first time ever. Couldn't get it lined up, so I had the bright idea to put the shifter in reverse, line up the cam, and go back together so it would be lined up. On the trailer it worked like a top. Reverse shift locked, front shift unlocked. Got it to the water and front throttle was reverse and reverse throttle was forward with it locked down in reverse throttle but being forward gear and vise versa. Took it apart again and it just had forward no matter what I did with the shifter. Took it apart again and now I believe it just has reverse no matter what I do to the shifter. It is driving me nuts to the point I just got home from work at 11 pm and tried it again with no avail.

 

[jlconrad24]

Re: 1973 Mercury 650 Nightmare

I had a praise along with another question. I was searching other post trying to find an answer and read the post from charlie 741 about the little spline shaft being the F-N-R shifter. I was turning the shaft every time I had it apart, but did not know what to look for when I was turning it. He explained neutral was free turn both ways, which I pretty much got that one, but that reverse was locked both ways, and forward locked one way but free wheeled with a click the other. I took it back apart and began turning my spline shaft back and forth but it was not making a difference. I then began digging into the lower unit to attempt research to see what the shaft was supposed to turn. Only to drop my prop, bend the end of a blade, and crack it trying to straighten it back up and finding that my impeller is missing two and a half blades. But then after I got frustrated I took a pair of channel locks to the spline shaft and realized I was never turning it far enough. I would turn it from side to side until it hit what appeared to be the end, but was actually with a little torque just the shifting point. So I was putting the shifter in all different directions but never had the cam properly lined up because the spline shaft was never properly lined up, and I had never actually shifted the lower unit in any other gear than the one it came apart in. Put it all back together in reverse with the prop being locked both ways and the cam at its highest point( straight back under the lock lever), and wouldn't you know it everything turns the way it is supposed to turn and locks when it is supposed to lock. Which brings me to my next two questions. If i have a really good stream off water, but two and a half blades are missing from my impeller, should I replace it now or wait until the stream slows down? And question two will the 1/2 crack in my aluminum prop be ok or do i need to send it off to get rebuilt again, considering it was bent when I got the boat and had to get it rebuilt before I could even put it in the water? I thought the post from Charlie 741 was very helpful and thought I would share for any other beginners like me. ( Mechanically inclined on just about everything, but boats). I would get the prop redone, and get a water pump kit for it right away, but things are tight and I am still having the running issue at full throttle, so I was just wondering if this stuff would get me by until I get the running issue straightened out and make sure it is a keeper.

 

[mmf]

Re: 1973 Mercury 650 Nightmare

you MUST put in a new impeller, I would put in a impeller kit which has all the seals too, your bogging issue probably results from the idle screws being too lean, with the boat in the water, engine warmed up and cover off, turn idle mixture screws equally 1/8th turn counter-clockwise and try giving it gas again, if still bogging down, turn the screws another 1/8th turn CCW again until bogging ceases.............PS, cracked prop blade will cause you problems when it's under full load and probably break off running causing out of balance condition on prop shaft (bad).............

 

[jlconrad24]

Re: 1973 Mercury 650 Nightmare

Thanks for the info. I will call East Side Marine and order a impeller kit right away. The guy that had the boat before me ended up telling me he replaced the the floats in both carbs because the were both cracked and full of gas. I have noticed when I pump up my prime bulb fuel starts dripping out of the intake on my top carb and it just seems there is a lot of fuel on the outside of the carbs and dripping off of some type of screw with a spring on it at the bottom of the carb. i am assuming that is the bowl drain. I was thinking about digging into the carbs but they do not have removable bowls like my ATV's and tillers and such. I found a 12 page expo on removing the carbs, but know nothing about timing dual carbs or anything like that. Wondering if I should dig in or find someone who knows what they are doing. I got a heck of a deal on the boat, but marine shops just want to much in labor charges just to pull in their garage. Most around here said it would me minimum of $150 just to look at the carbs, plus labor on parts on what ever it takes to fix them.

 

[Wingedwheel]

Re: 1973 Mercury 650 Nightmare

The carbs are really very easy to rebuild. After you re-assemble everything, search the posts for "link & sync. Thats also very easy. I hope this helps.