Inline 6 150hp how to test coil??

[sourbsted]

Just wondering on how to test coil. It runs ok on idle but won't get up on plane. Had machanic in the boat, he suspects weak coil.
Everything else is good! Carbs, link etc..I need to know how to test coil..
Tested the tower of coil to earth and shoots 1/4 of inch of spark..

 

[Lone Duck]

Re: Inline 6 150hp how to test coil??

Just wondering on how to test coil. It runs ok on idle but won't get up on plane. Had machanic in the boat, he suspects weak coil.
Everything else is good! Carbs, link etc..I need to know how to test coil..
Tested the tower of coil to earth and shoots 1/4 of inch of spark..

do you have a VOA meter or a DVA meter ?

 

[sourbsted]

Re: Inline 6 150hp how to test coil??

I don't much about this stuff.

 

[sourbsted]

Re: Inline 6 150hp how to test coil??

Rubbish in the seat

Top carb was on and off leaking in the water, now Iknow why!

 

[Chris1956]

Re: Inline 6 150hp how to test coil??

There is a ohm spec for the coil. Hurricane Sandy took my service manual, so I cannot provide it. I doubt you have a coil issue, but it is possible. Check spark plug wires for arcing to ground. Check compression in all cylinders. Inspect color of spark plugs. Watch for ones that look brand new, as they may be steam-cleaned by water infiltration.

BTW a coil is $25. Just replace it if you want....

 

[sourbsted]

Re: Inline 6 150hp how to test coil??

There is a ohm spec for the coil. Hurricane Sandy took my service manual, so I cannot provide it. I doubt you have a coil issue, but it is possible. Check spark plug wires for arcing to ground. Check compression in all cylinders. Inspect color of spark plugs. Watch for ones that look brand new, as they may be steam-cleaned by water infiltration.

BTW a coil is $25. Just replace it if you want....

Your right chris, I doubt the coil is bad, Me and the oldman tested the coil pole to the ground, It had a spark over a quarter inch. The top carb had rubbish in it and caused the motor to get flooded with fuel. The spark plugs were very wet looking, like they had been drowned in fuel. The machanic who water tested my boat thinks the coil may be bad, but he maybe comparing it to his 89 model limited edition inline 6.

 

[quicktach]

Re: Inline 6 150hp how to test coil??

I may have missed/forgot something ...what was the problem with the motor that started you tracking down the problem? You need the manual to get the resistance of the coil; then use an ohm meter. Check all plug wires for electrical leaks to ground. Any cracked wires ?
Any external track marks on the plugs ?

I agree the crud on the seat is a problem!

 

[Lone Duck]

Re: Inline 6 150hp how to test coil??

VoA meter coil test
test leads between + and - coil terminals . Ohm scale Rx1 Meter reading .01-.02 ohms .
Between coil tower and either + and - coil terminal Ohm scale Rx1000 no continuity
Between coil tower and engine ground Ohm scale Rx100 57-73 ohms
If meter readings are not as specified, replace ignition coil.

Hope this helps.

 

[sourbsted]

Re: Inline 6 150hp how to test coil??

I may have missed/forgot something ...what was the problem with the motor that started you tracking down the problem? You need the manual to get the resistance of the coil; then use an ohm meter. Check all plug wires for electrical leaks to ground. Any cracked wires ?
Any external track marks on the plugs ?

I agree the crud on the seat is a problem!

When me and the machanic first put the boat in the water to carry out the water test, he pulled the engine cowling off, and we noticed fuel pissing out of the top carb. I was spewing big time! then the leaking stopped. So he continued trying to adjust the mixtures, but in the mean time the carb was on and off leaking. He beleaves the coil maybe weak, but i think the motor was getting drowned in fuel. I had the boat doing 40mph a few weeks ago, and i was going for a while (easerly 5 minutes of the boat planeing). Its just getting the cranky old girl on to the plane is the problem.
The machanic offered to test the coil at his work shop in a couple of weeks, I would like to do it sooner.

 

[sourbsted]

Re: Inline 6 150hp how to test coil??

VoA meter coil test
test leads between + and - coil terminals . Ohm scale Rx1 Meter reading .01-.02 ohms .
Between coil tower and either + and - coil terminal Ohm scale Rx1000 no continuity
Between coil tower and engine ground Ohm scale Rx100 57-73 ohms
If meter readings are not as specified, replace ignition coil.

Hope this helps.

Thats a big help! I cant find this in the merc manual.
cheers

 

[mercurymang]

Re: Inline 6 150hp how to test coil??

Sometimes those manuals can be so frustrating. If you find a good one, gaurd it with your life.

 

[sourbsted]

Re: Inline 6 150hp how to test coil??

VoA meter coil test
test leads between + and - coil terminals . Ohm scale Rx1 Meter reading .01-.02 ohms .
Between coil tower and either + and - coil terminal Ohm scale Rx1000 no continuity
Between coil tower and engine ground Ohm scale Rx100 57-73 ohms
If meter readings are not as specified, replace ignition coil.



I carryed out a quick coil test: testing the leads on coil bewteen the + and - it was .01 ( should be .01-.02) Good!

Then I tested the coil tower to engine ground ohm scale Rx100 my result 32 ohms (suppose to be 57-73 ohms)

So it looks like the coil is weak then?? F#@ked?

so will this coil be ok?

MERCURY MARINER NEW IGNITION COIL OUTBOARD 6-225HP O/B | eBay

 

[Chris1956]

Re: Inline 6 150hp how to test coil??

I guess the question is how accurate is your VOM? I had one that I thought was accurate, until I determined it could not tell the difference between 400ohms resistance and an open circuit. That was a cheapie radio shack special, and it went into the trash that day....Replace the coil and move on.....

 

[sourbsted]

Re: Inline 6 150hp how to test coil??

Hey chris, does it look like that coil would be ok? Doesn't look like it would mount on the existing aluminum bracket.

 

[Lone Duck]

Re: Inline 6 150hp how to test coil??

VoA meter coil test
test leads between + and - coil terminals . Ohm scale Rx1 Meter reading .01-.02 ohms .
Between coil tower and either + and - coil terminal Ohm scale Rx1000 no continuity
Between coil tower and engine ground Ohm scale Rx100 57-73 ohms
If meter readings are not as specified, replace ignition coil.



I carryed out a quick coil test: testing the leads on coil bewteen the + and - it was .01 ( should be .01-.02) Good!

Then I tested the coil tower to engine ground ohm scale Rx100 my result 32 ohms (suppose to be 57-73 ohms)

So it looks like the coil is weak then?? F#@ked?

so will this coil be ok?

MERCURY MARINER NEW IGNITION COIL OUTBOARD 6-225HP O/B | eBay

Run your engine with coil as is. When your carb starts to leak, shut down and check spark plugs. If wet,swap that coil with one of the others. If that carb stops leaking , and another starts, then it is the coil. If the same carb leaks, then you have a fuel problem.

 

[sourbsted]

Re: Inline 6 150hp how to test coil??

The carbs dont leak anymore, the motor runs ok on the muffs.
I want that coil to be 100%. Hardest thing is waiting for the coil to come USA to Aus.. probably take a couple weeks..

 

[Lone Duck]

Re: Inline 6 150hp how to test coil??

The carbs dont leak anymore, the motor runs ok on the muffs.
I want that coil to be 100%. Hardest thing is waiting for the coil to come USA to Aus.. probably take a couple weeks..

Thats a bummer!!

 

[sourbsted]

Re: Inline 6 150hp how to test coil??

Yeah, two months I have been trying to get this motor going right.
That coil in the eBay link there is different to my inline 6 coil but I could adapt it to work. The aluminum bracket only needs to clamp the new coil in place.

 

[Chris1956]

Re: Inline 6 150hp how to test coil??

Sour, That coil looks to be for the ADI motors. It also looks like you could stick your old metal jacket on it and it will bolt up, but I cannot be sure it will work or fit. Aren't there any junkyards around you? The coils hardly ever go bad.

 

[oldman570]

Re: Inline 6 150hp how to test coil??

Yes the carb inlet seat is in poor shape and very well could be leaking extra fuel into the carb causing a flooding condition. Would be best to replace it and the needle when time permits. The ingnition systems are sometine very confuseing as there 5 diffrent setups and some used the same coil/coils as others and some were only used for a few years then changed to a diffrent style while still looking the same. Most coils will have a part # made in the plastic case between the + &- small post and others will have indelable marker on the back side of them. From my research the motor is a 1975 and the ingnition system is a type 3 that was only used for around 1974 -1976. The coils for a 50 HP are the same as for alot of motors made in that time frame and othes. The 9.9 mercs used the same coils up till 1973 then the system was change but other coils colored red or green will work just fine.. Guess the design engineers had to come up with something diffrent every so often inorder to keep their jobs. Same as todays engineers if it works and the common man can fix it then it needs to be changed so they have to take it back to the dealer to get it worked on or buy another newer motor. Isn't life grand. JMO
Oldman570