Someone please help me with this.... I have a 1971 Johnson 50 HP and i got it from my dad. He said that it stopped running on the water. He took it to the shop to get looked at and the guy told him that it has a bad sensor coil.....

I looked up the engine and this year doesn't have a sensor coil. Does anyone know what it could be that the guy thought is bad? This has a timer base and sensor assembly and I have not replaced that yet. I have replaced the POWER PACK, AND THE IGNITION COILS and still nothing,

What does a timer base and sensor assembly do? Is that the equivalent to a sensor coil? If not what is the equivalent on this model engine? What else could it be??? How can I test the timer base to see if it works???

Well, if your dad had already had it checked and they said it had a bad sensor coil, why didn't you replace it first if you were going to just start swapping parts.

The timer base (where the sensor coil is mounted) controls the spark timing.

The stator has a charge coil that generates the intial voltage and feeds it to the power pack, the power pack amplifies that voltage to approx 275 Peak Volts, (nead special Peak Volt meter to test this) and feeds it to the coils, the coils increase it to several KV to fire the plugs. The sensor coil in the timer base tells the power pack when to fire each coil. If it's bad, the power pack never gets the signal to fire.

A quick check it to disconnect wires on terminals 6 and 7 of the power pack.  Connect an ohm meter between the two wires you took off and they should read 30 - 50 ohms.  

yeah i was going to swap the sensor coil, but i went and asked for the part at the outboard part shop they said that this model didn't have one. I then looked up the engine diagram online and could not find any part called a sensor coil. what it did have was an ignition coil, so i tried that first and then i referenced another motor and saw that the stator and the sensor coil where in the same spot on each motor and figured a stator did the same thing as a sensor coil.

Up until recently i didn't know that the timer base held the sensor coil. it just had it labeled as a time base and sensor assembly on the motor layout. I even had a post asking the difference between a stator and sensor coil!

I appreciate your information very much and think it should help me out greatly

instead of swapping out part after part, most might be good and costing you lots of $$, why dodn't you just take it to a shop and let them work on it. they can fix it right and will end up costing you less $$

I personnaly don't think that's always the best thing to do.   Depends on a person's own abilities and what kind of parts he's using.  The labor rates at most shops around these parts are at $90+ per hour.  On a V-6 OMC, dealer price for a power pack is close to $400 and takes close to an hour to replace so as  minimum, you're looking at $500 when going to the dealer.   I can get an aftermarket power pack for less than $200, or good used one for around $100, don't cost me anything to put it in.   I just did a set of carbs on a friends V-6.  All the parts in the carbs were still good and reusable so it cost him a total of $10 for gaskets.  He was having a bogg problem, his dealer quoted him $480 to do the carbs and said he would have to do them before doing anything else.  Ended up being the fuel pump and we installed an electric for less than $90, which works much better than the OEM pumps.  The dealer said it would be another $300 if he had to replace it.  For $100, we saved him $800 the dealer would have charged.  It cost me 1/5 to completely remain a powerhead from what it would cost you to have a dealer get one and install it.

Now, if you lift the cover and everything under it looks like something from another planet, then yes, you would be better off getting it done at the dealer.

i Agree with way 2 slow. I didn't want to be rude about it bue you hit the hammer on the head. I am not the mos electrically inclined but if the guy who looked at it told my dad that it needed a sensor coil than the logical thing to do is buy a sensor cooil and put it on. The problem I ran into is that this model doesn't have a sensor coil and I was not familliar with the synonyms of outboard motor snad did not not that a timer base and sensor assmbly is near the same thing. The guy told my dad it would be about 700 dollars to get it running and after I have replaced the power pack, the ignition coils and the stator I have still not spent that much. If the timer base doesn't fix the problem then I will take it to a shop and have it diagnosed. Then I will see what exactly needs to be replaced and do ti myself. I am about 95% sure that is is an electrical problem. and I consider the experience that I am getting and learning about what does what on this outbaord a good tradeof instead of jus having some other guy do it and still not know the ins and outs of this motor. and plus I can take alot more pride when I turn thatkey and it roars to life for the first time because i was my knowledge and work that got it running...