1981 200hp merc, hard time starting, ignition question

[workaholic]

Re: 1981 200hp merc, hard time starting, ignition question

would my regular clamp meter work (i am electrician)

Like i previously posted. I put a brand new deep cycle marine battery in it and it seems to spin quick,,, but who knows.

 

[j_martin]

Re: 1981 200hp merc, hard time starting, ignition question

would my regular clamp meter work (i am electrician)

Like i previously posted. I put a brand new deep cycle marine battery in it and it seems to spin quick,,, but who knows.

It's DC. A biased DC clamp probe would work if you have one. Most electricians carry AC clamp ammeters.

The cheep meter from NAPA is basically a movement that uses the magnetic field around the cable for deflection. Fairly crude, but useful.

hope it helps
John

 

[workaholic]

Re: 1981 200hp merc, hard time starting, ignition question

lol. I was just kidding when i asked if my ac ammeter would work. I know its DC i just thought it would be funny...

I am going to use the dc ammeter and see what comes..

 

[workaholic]

Re: 1981 200hp merc, hard time starting, ignition question

also can someone tell me if this is the correct shop manual for my year and model, why its so difficult to find the proper manual is beyond me.

eBay# 330282593938

Thanks
Eric

 

[j_martin]

Re: 1981 200hp merc, hard time starting, ignition question

also can someone tell me if this is the correct shop manual for my year and model, why its so difficult to find the proper manual is beyond me.

eBay# 330282593938

Thanks
Eric

That one is for serial # Csumthin and up.

The manual you need is 90-97658-3 (happens to be the one I use)

hope it helps
John

 

[workaholic]

Re: 1981 200hp merc, hard time starting, ignition question

just to make 100% sure everything i am running that should be. This is my first season with this boat and motor and this is my first big motor....

What size of battery should I be running? My battery is a brand new Nautilous deep cycle marine battery, 625 cranking amps.

Is my battery maybe to small.?

Also i am running NGK Bu8H spark plugs

 

[j_martin]

Re: 1981 200hp merc, hard time starting, ignition question

just to make 100% sure everything i am running that should be. This is my first season with this boat and motor.

What size of battery should I be running? My battery is a brand new Nautilous deep cycle marine battery, 625 cranking amps.

Is my battery maybe to small.?

Also i am running NGK Bu8H spark plugs

Should be good. It should draw about 125 amps cranking. I have the middle group 24 in the interstate marine starting line, pretty wimpy for sure, and it snaps the motor to life in a heartbeat.

Check your starting current. Maybe you can put a rectifier on your ammeter.

 

[workaholic]

Re: 1981 200hp merc, hard time starting, ignition question

damn... i thought for sure my 625 battery was too small for the big 200. I had bought a 750 for my merc 50hp last year....

Now, to get my hands on a DC ammeter

 

[workaholic]

Re: 1981 200hp merc, hard time starting, ignition question

Well..... i didnt get my hands on a meter to test the starter output but i did try testing each coil at the plug caps 1 at a time to see how much voltage was coming out. 2 out of the 6 coils show to be good (in my opinion). If your standing behind the motor facing it, its the bottom cylinder on the right bank and the middle cylinder on the left bank that show good voltages. They have good fire up to 25 000 to 30 000 v. The other coils wont get anything over 10 000....

What voltages should I be expecting from the coils?

I havent checked all my grounds yet nor the plug wires themselves...

 

[j_martin]

Re: 1981 200hp merc, hard time starting, ignition question

Well..... i didnt get my hands on a meter to test the starter output but i did try testing each coil at the plug caps 1 at a time to see how much voltage was coming out. 2 out of the 6 coils show to be good (in my opinion). If your standing behind the motor facing it, its the bottom cylinder on the right bank and the middle cylinder on the left bank that show good voltages. They have good fire up to 25 000 to 30 000 v. The other coils wont get anything over 10 000....

What voltages should I be expecting from the coils?

I havent checked all my grounds yet nor the plug wires themselves...

How are you checking that voltage? The output of the coil should be limited by the firing of the plug. High voltage would indicate an open somewhere in the secondary circuit or plug itself. If you're firing those open circuit, the low voltage coils might be arcing between the coil and the metal they're mounted on. There should be a visible arc track or crack on em.

my 02
John

 

[workaholic]

Re: 1981 200hp merc, hard time starting, ignition question

I used a coil-on plug spark tester form Napa. All i did was pull off 1 spark plug cap at a time and installed the tester in each cap (leaving all plugs in the cylinders) and turned over the motor. Adjusting the tester from 10 000 to 30 000.

 

[j_martin]

Re: 1981 200hp merc, hard time starting, ignition question

Like I said, look under the coils.

 

[workaholic]

Re: 1981 200hp merc, hard time starting, ignition question

ok, i will remove the top casing blocking the view of the coils and retry.

I will try and get that done tomorow, then let you know what happens, should i be seeing arcing?

If there is no visible arcing between the coils or the plates and the same results happen as today, would you say the power pack is fautly? or 4 of the 6 coils.... (what would be the odds of that)..

Can i test the power pack?

 

[j_martin]

Re: 1981 200hp merc, hard time starting, ignition question

ok, i will remove the top casing blocking the view of the coils and retry.

I will try and get that done tomorow, then let you know what happens, should i be seeing arcing?

If there is no visible arcing between the coils or the plates and the same results happen as today, would you say the power pack is fautly? or 4 of the 6 coils.... (what would be the odds of that)..

Can i test the power pack?

You can test the coil drive from the switchboxes with a DVA. I wouldn't condemn one without testing it formally.

Remove the coils and look for physical damage on the bottom of them.
Another thing you could do is swap the drive wires around to see if the weak sparks follow the wires, or the coils.

Odds are good a bunch of coils are cracked on an old motor.

hope it helps
John

 

[workaholic]

Re: 1981 200hp merc, hard time starting, ignition question

Update for you John...

I pulled apart the coils, inspected them and cleaned them. One of the coils's carbon ground pieces was broke... but i tried swapping the wires from one of the good cylinders to 1 of the bad ones. the problem followed the wire... So that eliminates my coils.

Also i now have 4 of the 6 coils reading 20 000v and up. The 2 bad cylinders i cant even get 5000 out of them.

The left hand bank are now all firing over 20 000. and the bottom cylinder of the right hand bank is firing leaving the middle and top cylinders not going.

So,,,,, my guess would be a bad powerpack due to the fact that it kicks in once warmed up and runs nicely. I am leaning away from the stator because 1 power pack seems to be fine. Would they not both be affected if the stator was bad??

What next...

 

[j_martin]

Re: 1981 200hp merc, hard time starting, ignition question

Update for you John...

I pulled apart the coils, inspected them and cleaned them. One of the coils's carbon ground pieces was broke... but i tried swapping the wires from one of the good cylinders to 1 of the bad ones. the problem followed the wire... So that eliminates my coils.

Also i now have 4 of the 6 coils reading 20 000v and up. The 2 bad cylinders i cant even get 5000 out of them.

The left hand bank are now all firing over 20 000. and the bottom cylinder of the right hand bank is firing leaving the middle and top cylinders not going.

So,,,,, my guess would be a bad powerpack due to the fact that it kicks in once warmed up and runs nicely. I am leaning away from the stator because 1 power pack seems to be fine. Would they not both be affected if the stator was bad??

What next...

Just for grins and giggles, remove the bias jumper wire between the switchboxes and run it. It's possible that one switchbox is killing a spark on the other one.

I lost track of which two cylinders are misfiring. If they are opposite in the timing order, ie 2 and 5, it could be a bad trigger.

I wonder if bad plug wires have caused overvoltage on the trigger circuits (switchboxes) killing them.

hope it helps
John

 

[workaholic]

Re: 1981 200hp merc, hard time starting, ignition question

If your standing behind the motor facing it. Its the top right and middle right cylinders that are down....

ALso i decided to call the previous owner of the boat (this is my first season with it). I asked him if he had any problems with it prior to selling it. He said ever sinse he had changed the throttle controls he had a harder time starting it. He said he and screwed one of the screws down too tight and had pierced a wire from the ignition causing the casing of the motor to liven up when starting the motor. It has sinse been fixed but i am wondering if maybe that fried one of the packs when that happened.

Eric

 

[j_martin]

Re: 1981 200hp merc, hard time starting, ignition question

Common parts are switchbox and stator........ or interference from the other switchbox through the bias circuit.

Do what I said about the jumper wire.

John

 

[workaholic]

Re: 1981 200hp merc, hard time starting, ignition question

wich wire are you talking about? is it the short wire that goes form the back pack to the front pack?

If the stator was bad would it not affect both packs?? Like i said, it cylinder, 1 and 3 that are down... Wich means that its the pack #1, correct?