I have a 1981 johnson 75hp charger. blew powerhead so i bought an evinrude powerhead that was omc identical. I have no spark. wiring issues.Thought johnson and evinrude was same wiring?

the following should help
OMC Johnson Evinrude Model Guide 1973 1990 Johnson Evinrude 2HP 40HP Outboards SERVCIE REPAIR MANUAL year...

Bruce,
Do you have the serial number of the motor? Reason I ask is twofold. Evinrude started using this model number layout as of 1980. Having said this, something is not making sense with the location of the "N" in your model number. Those last two letters as of 1980 are the year. Here is the chart. Letter on top with corresponding year below it.

I N T R O D U C E S
1 2 3 4 5 6 7 8 9 0

So... Example
1980= CS
1990= ES
2000= SS
2010= IS

You have E8RLNR which breaks down as:
E= Evinrude
8= 8hp
R= Rope start tiller steering
L= 20" shaft
N= 2nd year
R= 4th year

I would expect to see the N in the last spot:
1982= CN
1992= EN
etc.

Serial number is another way to identify the year.
This may hep point you in the right direction. Hope it helps.

marineengine.com/parts/engine-model-guides/omc-johnson-evinrude-model-number-guide/omc-johnson-evinrude-model-number-guide-00004.html

Regards,
Fred

It should be 15hp, year 1975.
Driver coil is : 0763810
Ignition coil is: 0502880 OEM OR 18-5196 Sierra marine parts

clean the carb jets etc and check fuel pump diaphrams not hard or perished ! balance the carbs also !

Any spark at all?. The test gear is usually a dealer item.

Looks like this may be a 1982 model. See... http://www.marineengine.com/parts/engine-model-guides/omc-johnson-evinrude-model-number-guide/omc-johnson-evinrude-model-number-guide-00002.html

first, do not use the spark plugs to test for spark. They could be fouled. (another lesson) use new plugs or a spark tester, This a HOT (powerful) ignition system so be careful. Test for spark. No then, find the black wire with the yellow tracer is the ignition kill circuit, (or it was, should still be) I would disconnect it from the ignition switch and test for spark. Do not touch this wire during or after testing, it will hurt. if you have spark, ground the wire back to the terminal to discharge. You probably have a bad key switch. more if this does not work

What you have is a bunch of parts that you need. There are very few repair shops that would consider the repair. Being an employee many years ago of such parts....Try googling, Antique motor parts/ johnson. or elaborate as OMC / Evinrude/Johnson. You can still find a parts guy that can help you (very rare) search the web and hope it turnes out Okay! BeeCee

2.38 in the surface

I would try a johnson/ evinrude/ bombardier dealer for the diagram. OMC was bought out by them so they should be able to help. However in the marine industry it can be hard any literature on older products b/c they only produce a limited amount of their products.