Mercury 60, 1985 , A139746 , Ignition/Carb/Switchbox Issues

[w2much]

I checked the spark on all three cylinders and it is strong, jumps a 3/8 gap easily. I have a Seloc manual which shows the firing order and wiring diagram for the CDI to the coils to the 1,2 and 3 cylinder which I have followed. . The motor and manual have 1-3-2 as the firing order and the top cylinder as #1, middle as #2 and bottom as # 3. The spark firing order seems to be wacky. I have gotten the motor to run but top and the bottom cylinders seem to be switched. The middle cylinder fires and will keep the engine running. I can switch wires and coils for the top and bottom cylinders and it still wont run right. Can a bad CDI or trigger give symptoms like this ? I will try a timing light today but feel it will only verify my thoughts on what is happening.

 

[wrench 3]

If there is good spark at all the cylinders and the switch box is wired correctly, the ignition system is probably working OK.
However, my manual lists two possible firing orders the 1-3-2 or 1-2-3. It says that the correct order should be cast into the powerhead.
Other than that, test the compression.

 

[w2much]

I have been reading and messing with this thing for quite a few days. I am not certain the switchbox is an original Mercury box.. I saw an old diagram in a manual I have. I switched wires around and got lucky. My Seloc manual is either dead wrong or my switchbox is wired differently internally .I have seen this switchbox sell new for as low as 21 dollars to as much as 230 new. Is there a Chinese copycat here or what?
None of the diagrams I found for that motor worked.I now have the motor running, starts right up and all cylinders are firing. I too saw the two different firing orders in my manual. I was wondering if that is acomplished both mechanically and electronically through the switchbox or just by a different switchbox altogether. Any thoughts on this?
Now on to another issue. It is not charging, I have found the rectifier is bad. I have a new one here, I will install it tomorrow. The other issue is that it idles way too fast. I did not replace the throttle plate springs when I rebuilt the carburetor, I never do but will in the future., Hopefully after I install them the plates will close all the way as they should. I appreciate your reply.

 

[wrench 3]

They would have had to at least change the crankshaft to work with a different firing order. As near as I can find out they use the same switch box but change the wiring.
Did you check the synchronization?

 

[w2much]

i have to ask. What syncronizing? I guess in my befuddled approach I checked and thought and stared at it all. Finally against the manual I put #1 coil to #1 cylinder, #2 coil to #2 cylinder and # 3 coil to #3 cylinder. that worked. Now my issue is to bring down the idle. Cant seem to do it. Perhaps an air leak combined with a faulty carb rebuild.Bottom carb seems to be leaking through the nozzle into the throat. How do you seal the nozzle after it has been removed for cleaning? I will try again tomorrow with the cleaned carbs from the other 60 I have.

 

[w2much]

7778A3 Switchbox for Mercury 60 HP and others

Just curious here if anyone is familar with or has used the after market switchboxes seen on auction sites. The OEM Mercury switchboxes have a price of about 225 dollars. The aftermarket switchboxes are selling for as low as 21 dollars. I would like to know if the wiring is the same? What is the quality? Why is the 7778A series the only one being mass produced and marketed? It seems as I have one in a motor I am working with and will need another for a different motor I will work on later. Anyway 21 dollars is a heck of a price for a new switchbox. Curious how they came to be and what users have experienced with them. Thanks.

 

[wrench 3]

There should be a section in your manual on "timing and synchronizing". Both the ignition timing advance and the throttle plates on the carbs are controlled by your hand throttle. The synchronization is the relationship between the two. One of the symptoms if it's off is high idle.
If there's gas leaking into the carb throat it's probably flooding.

 

[w2much]

I did a temporary adjustment on the throttle plates to assure that they are both completely closed .I loosened the screw on the throttle lever to do this. That is how I know there is an air and fuel leak. The fuel seems to be coming up through the carburetor nozzle not certain though. I did remove it not sure how to seal it in place. Loctite? Pulled the carbs today, cleaned my other set and will try them tomorrow.Hope it works.

 

[Faztbullet]

Best advice is to buy 2....These are offshore and South American knock offs of the OEM boxes. The grey plastic case models doesn't work on V-6 models as the bias circuit range is to high and timing is effected. I had customer replace his and bring to me to set timing has he couldn't , nor could I as boxes had defect. Put Serria boxes on and worked perfect.

 

[w2much]

I can not swing for a new one from Merc. I usually try to purchase used OEMs when needed and have had very good luck with them. I have an older 60 HP merc I am working on which has an aftermarket switchbox on it. Figuring out the firing order was a bit frustrating as it was not as the manual showed.Now I am having an issue with a high idle. Today I am going to switch the carbs with others I have to see if the issue is the aftermarket box or something else. Reason I posted this was to get input from others with similar experiences with these switchboxes. I appreciate yours.

 

[w2much]

Merc 60, 1985 Can't slow down and bottom carb issue

Messing with this engine. Switchbox issues posted. Just put on a second set of carbs. Both sets were cleaned and rebuilt. Motor has super high idle that even with the throttle valves close tight can not adjust to slow down. Significant perhaps is that the bottom carb on both sets seems to have fuel collecting in the throat then of course down into the cowl. I am fairly adept at carbs so I am wondering what may cause this issue. Runs to fast on both sets of carbs and both bottom carbs from each set with fuel in the throat coming from ?????????? Motor runs the same and has the same issue with either set of carbs.

 

[wrench 3]

Let us know how it goes.

 

[w2much]

Today I installed the second set of carbs after a good cleaning. Motor ran as it did yesterday. Quick start just can not slow down the idle. What one thing I noticed was that once again in the bottom carburetor through fuel was pooling a bit. At the front of the throat there appears a small puddle. Same as yesterday with the first set of carbs.I went around the carbs and crankcase seam spraying a starter fluid to check for air leaks but found nothing.. Becoming again frustrated I took the switchbox out of engine # 2 also. This was or is a OEM Mercury switchbox. Motor still runs with way too fast of an idle. So I have switched carbs, switched switchboxes and assured the throttle valves are closed and still a high idle. I like a challenge but only after success. Any suggestions ?????

 

[Chris1956]

What is the idle timing you are seeing with carbs closed?

 

[w2much]

I will check that today. What should it be. I can not understand where the fuel is coming from for this thing to idle so darn high. I mean it needs fuel to run like that. Can't all be timing. I loosened the throttle lever to insure the throttle plates are closed

 

[racerone]

But it is the timing that is the issue.------Throttle plates have holes to let in a certain amount of air / fuel.-----Idle RPM is controlled by retarding the timing.------Lots of folks look for air leaks but never find any on these 2 stroke motors !!

 

[w2much]

Racerone, I think you have me correct. I have been looking for air leaks. Of course I have probably or certainly screwed up the link and sync but should the idle at least respond to my moving the trigger plate forward and back to try to get a response, even if it is wrong ?

 

[w2much]

Can a bad trigger or stator or switchbox create this issue I am having?

 

[GA_Boater]

The three threads you have going on this have been combined into the original. It helps to know what has been suggested by all members or you get redundant advice. And you have asked switchbox and carb questions crossing over in the three threads - Most confusing.

 

[w2much]

I know I am confused.