Mercury 650cc 65hp Carby problem i suspect...

y2jericho

Petty Officer 2nd Class
Joined
Aug 30, 2002
Messages
146
Well. I paid $350 or so US dollars for my mechanic to fix up and service my Mercury 650cc 65hp perfectly... Fix up the carbs which includes cleaning them and changing the stuff in them thats meant to be changed. Also replacing impellar .. Sealing a screw which was leaking water from lower unit with silicone (actually helped).. Changning plugs.. Lubing up everything and changing gear oil. Adding a rectifier and all these others things he did. Good amount of work even though he charged me a little to much (though im willing to pay it if he makes it sea worthy so i don't get stuck in the middle of a bay on a stormy day with no boats around...<br /><br />Anyway the problem:<br /><br />Wipe open i had the motor going and it was working alright but it didn't sound like it was working really hard. Hard but not loud enough and gutsy if you konw what i mean. I slipped it into gear off i wen't on the mayden voyage.... At wide open i was going maybe 15km/h maybe 20 but damn it was so slow.. Anyway i did some circles to at least check out the steering if it was alright. Then conc conc conc Motors dead.. Couldn't start it and it turns out the tank was tilted and the tube wasn't picking up fuel (my mistake fitting the tank. Anyway the tankw as nearly empty so i put the 2nd one in which was full... Motor started great. but this was after i got towed from the cliffs rocks to the ramp but i did not take off this time because i was so scared i wouldn't get towed in a worst case scenario because i was lucky the boat was going around the rocks and i couldn't row into the ramp as it was easy at least 1km away.. Anyway after pumping the primer bulb stiff there was petrol coming out of the side hole in hte engine.. So i took cover off and i realised it was coming out of the top carby (which explains 2 cylinders not firing properly... and the real slow speeds) When i pump the primer bulb stiff. I wait 5-10 seconds then i can see petrol pouring out of the top carby and then I am guessing the bulb isn't stiff anymore.. I haven't tried starting it because im scared it will go on fire.. Is it possible the mechanic didn't fit the carby properly or put the needle in right or something ?as i am suspecting this because i at FULL SPEED ABSOLUTELY i was going surely not faster then 15km/h like it was only fireing 2 cylidners.. (speedo's not hooked up yet lol :) Anyway any help would be appreciated.. Filter bulb were changed and i know for the fact the petrol lines are fine as i blew them through with a compressor and they are soft and not that stiff yet.<br /><br />Once again thanks a million bread rolls for all the help i have already recieved from you guys..<br /><br />This motors a 1970 Mercury T.b. 650cc 65hp. if i didn't already say it. And don't you guys agree the remote control in these boats is a bit crappy with the right hand side leaver being the throttle and the big left hand level being the gear.. And when i push the forward gear lower and lower shouldn't the throttle move forward with it to?<br /><br />Thanks
 

y2jericho

Petty Officer 2nd Class
Joined
Aug 30, 2002
Messages
146
Re: Mercury 650cc 65hp Carby problem i suspect...

i suspected it wasn't running hard enough on full throttle because it was running on 2 cylinders?
 

mellowyellow

Vice Admiral
Joined
Jun 8, 2002
Messages
5,327
Re: Mercury 650cc 65hp Carby problem i suspect...

inspect your bill from mechanic to see what he actually did to the motor. for $350 for all items mentioned, I suspect he did NOT remove/rebuild the carbs. to remove these 3 carbs, soak them clean overnight and install a crb kit is about 6 hr. labor as there are many items that have to be removed to get the carbs off.<br />fuel leaking from carb means a stuck float(prob.)<br />and if you tap on the fuel bowl on the side of the carb you may be able to unstick it.<br />post more info. on what's actually been done so far. perhaps I'm wrong and he's only charging you $25/hr labor or something???<br />regards,<br />M.Y.<br />ps. go out and purchase 3 new fuel pump kits and make sure you have new diaphrams installed.<br /><br />(edit) not awake.... only 2 carbs/4cyl...ZZZZZZ
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: Mercury 650cc 65hp Carby problem i suspect...

y2jericho <br />As Mellow stated, it sounds like a float needle is sticking open, causing the fuel to run out of the Carb. I would call the Mech. and ask them if they did or did not completly rebuild the Carbs, when they serviced it. I doubt it though! In which case, if I were you, I would just get the kits and do it myself. As for the throttle controls, the small lever is just a Warm-up lever for fast idle. When this lever is all the way down(Running Position), you would use the shift lever to select forward or reverse and increase throttle as you push or pull it farther, depending on what gear you're in..
 

y2jericho

Petty Officer 2nd Class
Joined
Aug 30, 2002
Messages
146
Re: Mercury 650cc 65hp Carby problem i suspect...

mechanics just up the road right now so ill ring him in 30 minutes because he will be back then. Anyway about the control box.. The right hand leaver moves all the way down to the bottom in tandem with the big leaver when i pull it back to get boat in reverse... But when i go to stick it in neutral or stick it in gear to go forward the right hand leaver doesn't move at all....
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: Mercury 650cc 65hp Carby problem i suspect...

Lever should be down all the time except when starting for the first time. As I said, it's a fast idle lever that should only be used to bump up the idle when cold starting. You may need to do some adjusting on it or it's sticking if it does'nt stay down. I can't remember for sure, but I think my '67 650 had that same control and I believe it had a "Catch" that would keep the lever down. But don't hold me to that, as that was some time ago.
 

mrmarvc

Cadet
Joined
Dec 16, 2002
Messages
23
Re: Mercury 650cc 65hp Carby problem i suspect...

Hey there y2jericho,<br />It sounds like you have the same motor as I do, I have a 1965 merc. 650 65 h.p. Had the same carb problems as you and I think it seems like that is solved. Now seems like possibly a weak fuel pump maybe, plus I think I have a shot impellor in the lower unit that is not pumping water through the motor and out the pee hole. This spring I will drop the lower unit and go through all that stuff. Let me know what you find out, as maybe we can help each other out with tricks since we have about the same motor and problems. My email address is: marvc@marshallnet.com if you would like to email me. Good luck and happy boating ;)
 

Cohoho

Cadet
Joined
Jan 10, 2003
Messages
28
Re: Mercury 650cc 65hp Carby problem i suspect...

Y2:<br /><br />I am the kind of guy that needs help rather than offering it, but I just had a very similar problem with my 1974 Mercury 650. I too thought that the left lever was the shift and the right lever was the throttle, but the left lever is both. As Rick pointed out to you and to me earlier, the right lever is only for warming up, then it is to be returned to the back or down position.<br /><br />What really threw me is that I moved the shift/throttle (left lever) almost all the way forward and the motor was still just above a fast idle. Well, with the right lever back all the way, push the left lever a little further. You'd be surprised what happens in that last half-inch that the lever moves. <br /><br />I was frustrated with the 20 MPH thing, but once I figured out how to use my controls, my boat pops right out of the hole and hums along.<br /><br />You may have other problems, but maybe just maybe your motor will run as well as mine once you try this.<br /><br />Good Luck!
 

Troy_from _Oz

Petty Officer 2nd Class
Joined
Sep 29, 2002
Messages
126
Re: Mercury 650cc 65hp Carby problem i suspect...

Y2<br />I have a 71 merc 650 which runs a MerControl control box. If yours is similar - and as rickdb1boat suggested, there is a little spring loaded catch at the rear of the control box that holds the fast idle lever in position when in gear. If you can't see it, look for a small ~3mm hole around that area. This is where it may have been once apon a time. mine recently went 'ping' and ejected the latching mechanism so ill have to do something about mine too. It should be pretty easy to replace.<br /><br />Cheers - T
 

y2jericho

Petty Officer 2nd Class
Joined
Aug 30, 2002
Messages
146
Re: Mercury 650cc 65hp Carby problem i suspect...

WoW thanks guys once again. Ill try everything out asap and will confirm the results. Mechanic told me to rbing it in possibly saying he did not put the carb back together properly. I will be trying everything asap. THanks again guys
 

PDS

Petty Officer 1st Class
Joined
Aug 15, 2002
Messages
239
Re: Mercury 650cc 65hp Carby problem i suspect...

As a side note on carburator rebuilds: new parts aren't always good parts. My example is with a twin-carbed snowmobile( It's a two cylinder-2 carb) Last fall I rebuilt the carbs using 2 carb kits and after putting the carbs back on the engine I started it and it ran fine. I than noticed it was leaking gasoline. I found that it was comming from the overflow tube on carb #2. I took that carb off and took it home. I took fuel bowl off and, using a hose with water attatched to the inlet tube tested the needle and seat. Result: faulty new seat and/or needle. I put the old one on and retested-no leak. New is not always better. P.D.S.
 
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