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Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 10601
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
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I have a 1986 johnson outboard v4 90hp 2 stroke. I bought

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I have a 1986 johnson outboard v4 90hp 2 stroke.
I bought the boat in 2007 and it has been sitting since 2008.

I had the carbs rebuilt and cleaned.
Changed plugs, and fuel filter.

Starter is bad so i have been useing the pull cord

Last nigh boat started up first pull no hesitation and idled great on the hose. Today put it in the water and it would not start. Gets fuel but i dont think its getting spark.Its like the key is not on but it is.The only thing i did since last night is i left the key on all night but battery is still fully charged.

I was thinking mabee the key switch is not working? but it turns the starter and when i push the key in it activates choke.

The alarm for the oil usually sounds when you turn the key but has not been working. I took the alarm out and plugged it to the batery and it works fine.

Hi my name isXXXXX will assist you.


Unplug the main engine harness try starting. If the engine starts the key switch is bad, if not there is an ignition component failing. To test the ignition components you will need a peak reading volt meter. If the engine does start you will have to choke the engine to turn if off.


Post back with questions.

Customer: replied 5 years ago.

where do I find the main harness?


What does it look like?


how would i choke it?


I have a multi meter but not sure what apeak one is? I am not 100% confident in using it would need tips.

Thank You

The main engine harness is the big red plug. To shut engine down just disconnect the fuel line.

There are some tests we can perform on the ignition components but they are not as accurate as the peak reading volt meter.


Disconnect the main harness and get back to me if the engine doesn't start. This test eliminates the key switch.


Post back with questions.

Customer: replied 5 years ago.
I will try itto in the morning. Do i accept awnser now or after i try sugestions?
Will i still be able to ask follow up questions

Ok, You can always continue after you have accepted.

Tan and other Boat Specialists are ready to help you
Customer: replied 5 years ago.

I disconected the harness and it started right up.


Does this mean i should replace the ignition switch? or could it be the emergency kill switch?


The warm up lever broke off when i was trying to take aprt the control box. do you know where i could get a replacement?

It could be either one, disconnect the black/yellow wire from the key switch, if the engine starts the key switch is bad, if it doesn't the kill switch is bad.


The warm up lever you will have to get from your local dealer the p/n(NNN) NNN-NNNNor from this link. click here Diagram of 1986 J90TLCDC Evinrude / Johnson Johnson Outboard REMOTE CONTROL Diagram and Parts Post back with questions.

Customer: replied 5 years ago.

Thank you so much for your help.


one more question. what is the little round nobe under the key for?

Your welcome. Thats the throttle friction adjustment. This is if the throttle handle creeps up tighten the knob and the handle will stiffen up and stop creeping up.


Thank you...Tan

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Customer: replied 5 years ago.

Hi Tan

I just installed a new ignition switch but I am still having the same problem with boat starting. I disconnect black/yellow wire boat starts.

The new switch was almost identical but a little different. Old witch had letters for where the wires connect.... M S C A M B. new switch is marked M B M C I S.New switch is a Sierra MP39760. Not sure on origional part number. This is what they sent me when i imputed year and model.


if this switch is right can you help with color of whire to each letter?


Also I ordered a starter because the old one would turn but not go up and turn engine. If i jump it directly from sylonoid it would go up but turn engine too slow to start it.


I installed new starter and the problem is identical. I didnt try to chump directly to sylonoid this time.


Any help is much appreciated

The A and the I are the same battery. Check the voltage at the start solenoid while cranking the engine must have 9.5+ volts. If the voltage is below 9.5 you have a bad connection or bad battery cables from battery to engine. Low voltage will make the starter turn slow. If the voltage is good at the starter and solenoid while cranking the starter is bad. Check your voltage going to the starter 9.5+ volts while cranking. graphicHere is a wiring diagram.


Post back with questions.

Customer: replied 5 years ago.

OK..... LOL I checked voltage at solonoid. I have 12 v. while cranking starter between10 and 11v. but does not engage. I jump the wires from solonoid and still turns but does not engage.

Does this definately mean my new starter is bad as well??

Check the voltage directly on the starter while cranking. Positive and negative. Check your ground cable for corrosion.


Post back with findings.

Customer: replied 5 years ago.

13v at starter pos and neg

While cranking the engine over? You must do this test while cranking the engine over. The voltage will drop, but must not drop below 9.5 volts.
Customer: replied 5 years ago.

The gear on starter does not go up and engage engine so how would i do that?

I took reading while turning the key and start spins but doesnt go up to engage engine. New starter and old do the same thing

We aren't interested in what the starter does at this point we are trying to find out what voltage is getting to the starter. The starter not engaging is an indication of low voltage to the starter. Just check the voltage on the starter terminal while cranking the engine the starter doesn't matter right now. Post back with the voltage reading on the starter terminal while cranking.
Customer: replied 5 years ago.

You are not going to believe this...... I had the battery cable on batery backwards. You might not believe it but im not usually that dumb. cables are not marked well. Switched around and the key switch works, old starter work, genius ha.....


Sometimes we over look the obvious. Glad you got it. Can you return the starter?
Customer: replied 5 years ago.
i dont know. i think electrical parts cant.
Can't hurt to ask.
Customer: replied 5 years ago.
Very true.thanks again for your help
Your welcome....Tan
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