Mercury 650 3 cyl Link N Sync Questions

[merc850]

Yes mine works that way, good for slowly advancing throttle for trolling,skiing etc. Max RPM range is 4800-5300 try for 5300.

 

[gholmesjr]

Ok. Sounds good. I was going to test it tonight, but the wife wants to go out looking for mushrooms instead. So I will be testing it this weekend sometime. Will let ya know what I find out. Again, thanks for the help Merc.

 

[gholmesjr]

So I was able to talk the wife into taking the boat to the dock for a bit after shroomin. At idle without being in gear I got it down to 850-950 rpm. In gear I got it to sit around 600 rpm, however at WOT it wouldn't go above 1900 rpm. I did notice that fuel was leaking from the quick disconnect, not a lot, but a steady amount. I would take it that this would not help matters by any means. I wasn't able to bypass the disconnect yet. I am going to get new hosing, clamps, and a new female and male quick disconnects tomorrow. All three plugs are getting spark when they should be as I put the timing light on all of the wires. On the first wire I have at idle 3-5 deg at WOT I am at 23 deg. It sounds good, just not getting the rpms we should be and it seems to not really like going below 1000 before it starts sounding like it is skipping. Suggestions? I feel like we are almost to a point where we got it working good! Thanks merc!

J.T.

 

[gholmesjr]

Another thing that I forgot to mention last night. I noticed that the battery cables have some play in them by the motor and will actually cut out power to the motor while trying to start it. I have to wiggle them around to get it to connect again and then to fire the motor up. This is just one of the issues, but could this also be causing it to perform badly? Or just a side issue that needs to be fixed?

 

[merc850]

Well that explains the burned out rectifier, you'll have to rewire or clean all the connections.If you're serious about this and future motors a 1975-78 Mercury manual is a great investment- ebay or dealer.

 

[gholmesjr]

Ok Merc. So this is what I've done since we talked last. I rewired new cables from the motor to the battery, starts up much stronger now. When I got it running, I checked for sparks coming out of the wires, there were none. I got new fittings to replace the old ones that were leaking fuel. This caused fuel to dump out the front of the carbs a bit, so I took the carbs apart and adjusted the floats. They are within spec, but the needle barely moves. Still have gas dumping out the front. Not a lot mind you, but some, however the motor also isn't timed correctly because I can't get it to be under 1000 rpms and put it in gear, it dies. I would have to have it above 1000 rpms in order to even get it in gear before it dies, but I am worried about the lower unit at that rate. Any suggestions on where to look next? Could it be a bad switch? Could it be reeds? Does this motor have reeds? Thanks Merc for your help!

 

[gholmesjr]

Sorry. Of course these motors have reeds, sheesh. It was late when I wrote that out. Do you think that could be a cause? I am going to test it this week to see if I am getting any sucking on the carb or if that's the reason why gas keeps spilling out the front, perhaps they are stuck.

 

[merc850]

Sounds like your needle seat assembly is sticking, where did you get the setting info from.
Look at the second manual page posted in the previous page to set the idle speed stop, you set the low speed needles 1 1/4 turns out while engine is in gear running on lake at 1200 rpm and then adjust them one at a time until motor is running smoothly. To test reeds put your hand over carb while engine is at 1/2 speed and feel for suction.

 

[gholmesjr]

Hey Merc. Thanks for the reply. This is what I followed: http://www.myoutboardengine.com/carb650_6.html

 

[merc850]

Ok but the other setting is missing
If your engine has this type of carb cover undo the brass fitting remove and discard the filter inside

 

[gholmesjr]

Merc-

Thanks for the illustrations. I have set both of the carbs to what you've supplied. I am still getting fuel pumping out the front of them. I think now though, that if the motor isn't using all of the fuel and using it efficiently the fuel will spill out the front of the carbs. I checked for suction on the front of the carbs and the bottom carb has more suction than the top carb, but I can feel air being drawn into both and covering them choked the motor.

Here's my status now.

I checked for spark on all three cylinders while it was running, I pulled the second wire off while it was running and it did not drop RPM. I did get a rather large shock to my hand. I do get spark to all three cylinders, but I would think pulling a plug wire while running the rpm would drop or the tone of the motor would lower or it would idle rough. It did not which tells me perhaps I'm not running on all cylinders, however I am getting spark to all cylinders. Also out of gear I was able to rev the motor to 5500 rpm.

So, I followed this youtube instructions on checking for a faulty trigger: https://www.youtube.com/watch?v=D-hBeGdE6oE

It shows that the trigger should fire on cylinder 1 when the the light is on wire 1 and it pulses, same thing for two and three. Mine shows that when connected to wire 1, it fires on 1 and 2 and sometimes 3. When it is on 2, it fires on 2 and 3 and when it is on 3 it fires on all 1, 2, and 3. So do I have a faulty trigger? It sounds like it to me. Unless this test doesn't work on 3 cylinder motors. If things aren't burning the way they should, that would make sense why the fuel is spilling out of the carbs. The pump is pumping the fuel that it is supposed to pump, but the cylinders aren't burning enough of it. Does this make sense?

Thanks for your help!

J.T.

 

[merc850]

Fuel spills out of the carbs if the motor is tilted up or the floats are sinking or carb needles are faulty (not shutting off at the right level). That trigger test is not for distributor spark systems - 1976 and on; is the cap clean inside? look for burned tracks; do you have the right new spark plugs L76V.

 

[gholmesjr]

The distributor cap is clean. In fact it is replaced cap from a salvage yard. No burn tracks. The spark plugs I have are the ngk BUHW type. They are brand new. Should I switch to the L76V? They are similar in build with no prong.

Thanks again,

J.T.

 

[merc850]

These are the right plugs (Nr.1)
Where is the fuel leaking from A or B?

 

[gholmesjr]

Merc-

I have the permagap NGK plugs, so those should be ok for this application correct? Also the fuel is out of A, but I really can't see where it is coming from but assume it is coming from A's location in the carb, B is not leaking. It comes out the throat of the carb and spills down into the collection tray.

J.T.

 

[merc850]

Must be stuck float - I can't think of anything else. NGK will work.

 

[gholmesjr]

Hmmmm...new floats and carb kit. I'm stumped at this point...

 

[gholmesjr]

So, I got the motor timed last night. Was able to finally get around 6k RPMs. But gas is pouring out the front of the carbs. I adjusted the needle and seat so it barely moves at all. Not sure what the problem is. Thinking another carb kit perhaps. See the video here:

 

[gholmesjr]

So, I decided to tear down the motor. Come to find out I had two reeds that are chipped and cracked. I have replaced those and now await seals on order. Going to be replacing all seals that I can before putting the motor back together. Will keep this thread updated with my progress so that if anyone else has these issues.

Anyone have any advice for putting things back together, like lubing things up and what not?

Thanks,
J.T.

 

[JMSurra]

Once you get it back together and your leaking-gas issue has been addressed, if you're still lacking power I would suggest you take another look at the distributor belt. If it's one tooth off in the wrong direction (I want to say to the left, but I can't remember which side ), it'll pop and will fight you trying to get it timed and tuned.

Also, it's very important that you use the proper instructions for aligning both the flywheel and the distributor. I have a service manual that shows a couple of different locations for the plastic timing indicator, but never showed the page shown here in this thread - which just happens to be the one for my motor. I sure could've used it when I was starting out! I checked your Serial number, and your S/N's batch is the same as mine (well, depending upon where you look it up. Another source shows your S/N - 3549507 - as a 1973-ish Merc). Mine's 4140802. In any case, if it looks like yours, the instructions Merc gave you should be correct for yours.

My plastic timing indicator just wasn't there, so I used the old tried and true method of popping the spark plugs and feeling the top of the #1 piston stroke using a small dowel stick. You're looking for that sweet-spot where it 'floats' at the top of the piston stroke. That's your TDC (Top Dead Center).

You can't be any more sure of TDC than that. At TDC, you'll see that the TDC mark on the flywheel is right at the spot where the timing indicator points to, or where the indicator was parked before it disappeared.. . . This will let you know whether the flywheel was taken off and put back on using the wrong bolt holes. In any case, the #1 piston never lies! No matter what year you have, that's how you can find your TDC.

When mine is at TDC, my distributor belt-driven pulley has a little pointer sticking out from its side that (when it's set correctly) rests just over a little extension in the casting below it. Mine's on the left side of the casting, but still over the casting.

I just wanted to offer that up as a good place to start. Being sure of your TDC and your distributor position is like laying a good foundation. Everything else rests on it. I hope this helps.

I'm staying subscribed and following your progress, J.T.! Good luck, and let us know what you find.

JM