mid 70's 115 johnson

[mid70sjohnson]

I have a mid 70 115 v-4 johnson with very little spark... sometimes i get good spark some times none at all... When i check the voltage coming to the power box via the coil wires i'm getting like 300 volts don't think that is enough...what could my problem be

 

[James R]

Re: mid 70's 115 johnson

This is a long drawn out diagnostic process. I recommend that if you don't have a manual then getting one would be the next step.

 

[emdsapmgr]

Re: mid 70's 115 johnson

You can look up CDI electronics on the web. They have some troubleshooting information on most outboards, esp the older ones. You can get an original factory service manual from Ken Cook Co., in Milwaukee.

 

[willamettejeff]

Re: mid 70's 115 johnson

300 volts from the power pack to the coils is exactly what you should have. The coils will then boost that up to spark voltage (30,000 volts or so). So the question becomes, when are you not getting 300 volts to the coils from the power pack, from the the stator to the power pack, or is the power pack at times not being triggered by the sensor coils? Does it fail only after it runs for a while and then start to work again after a cooling off period? Need more information on when the problem occurs. Don't know your year motor, but mine has 2 power packs. One for each side of the engine. Are you losing spark on both sides or on only one? Could try swapping the packs if the latter and see if the problem follows the pack. As others have said, a good manual will help you troubleshoot this problem.

-- Jeff

 

[mid70sjohnson]

Re: mid 70's 115 johnson

i just got the motor it is on a stand i'm not ready to run it yet... I wanted to make sure that it had good spark before i run it....The funny thing is that i am always getting 300 volts to every coil wire at the power pack the problem is the spark is off and on some times it's there some times it's not...

 

[boobie]

Re: mid 70's 115 johnson

What kind of meter are you using and at what settings??

 

[mid70sjohnson]

Re: mid 70's 115 johnson

not sure what brand meter is old one from my father... set at max 500volts direct current... It also seems that this motor does not have an i d plate so i can tell what year it is... I'm not sure how else to tell what year it is... If any one has any ways of telling i am all ears

 

[emdsapmgr]

Re: mid 70's 115 johnson

That engine should have a casting plug on the top of the engine block which will have the model and serial number. It's probably painted over, but the model number is the thing you need.

 

[crb478]

Re: mid 70's 115 johnson

If it is a mid 70's motor, 73 - 77, It should only have one power pack. Those motors are known for grounding problems so make sure that all of your wire connections are good and shiney clean. Make sure that the grounding straps are in good shape and add a few if you need. How do your coils look, any that are cracked should be replaced. The CDI electronics site will give you the needed info to isolate any component problems

 

[mid70sjohnson]

Re: mid 70's 115 johnson

thank you guys a ton i will begin the process from the cdi web site how ever i did not find the plug with the cereal number but i will look again when i get a chance.... I will post and let you guys know how it is coming along...

 

[boobie]

Re: mid 70's 115 johnson

To get an accurate reading on voltage outputs on these mtrs you should have a peak reading volt meter or else a voltmeter you can use a DVA adapter on.

 

[wilde1j]

Re: mid 70's 115 johnson

DVA adapter:
http://www.americastoolwarehouse.com...s/ESI-640.html

 

[mid70sjohnson]

Re: mid 70's 115 johnson

so i found the plug and the numbers i got off of it are 388398 rph I have researched the numbers and it has turned up nothing for me...

 

[emdsapmgr]

Re: mid 70's 115 johnson

That number is a part number and is unidentifiable. The round tag on the engine should have a serial number and a model number on it. Best guess is that this part number may be for the engine or the powerhead only, in the 76-77 timeframe. When the part number finally went obsolete, it sold for $ 2500.