1971 Chrysler 20 HP Coil Wiring

[Stewart Orchard]

New member, but I have been finding the iboats forum in every search result for outboard questions, so I decided to join.

I recently acquired a 20hp (202hc) Chrysler. looks clean with good compression. Closer inspection I found the top of the head has pry marks where the flywheel was removed. Points were dirty and cleaned, but still no spark. I have one bad condenser, a new pair on the way. However, I noticed that the two wires from each coil is attached to the points. Is this correct? Should one be to ground? if so, where?

Hopefully this engine can be revived. I've cleaned the carb and will need new fuel pup diaphragm and gaskets. Haven't checked on the gear box yet, Saving that until I have spark.

Parts appear to be difficult to find. Two differing coils on the motor, one is stock the other appears to be one utilized on Evinrude motors. The stock coils are no longer produced, could I use an equivalent coil from another engine if my coils are bad?

Thanks in advance

 

[jerryjerry05]

Looks like yours is a 1971.
Your right about parts being hard to find.
The points can look good and still need cleaning or filed??
Use a 120 or finer to clean the contacts, then check for spark.
Franz Marine might have the points ???or Google antique outboard parts.

 

[racerone]

I believe you will find that each cylinder has it's own ignition system.-----That motor will run very well on one cylinder.----Do not start changing any wires.---Some smaller MERCURY dealers may be able to help you if you talk nice.------Brunswick did take over FORCE which is really the old Chrysler line up.-----The coil shown for a 78 model 20 HP and magneto is listed at $136.------Your location ?

 

[Stewart Orchard]

It is a 1971.

Points were filed and cleaned. Could not find points googling the part number. They appear to have been out of production for quite a while.

My main question is about coil wiring. There are two small wires and the spark plug wire on each coil. Both the small wires are connected to the same location on the points contactor. This seem odd to me, but I have not messed with enough magnetos to know if it is correct.

racerone, I have seen these replacement coils. They are quite spendy, I was hoping that a more available coil would work should mine prove to be faulty.

 

[racerone]

Only one wire should go to the breaker points.----These coils / magnetos were the same year after year, not just a 1971 model----!! Your local shop might have a MERC-O-TRONIC magneto analyzer to test all your parts.----Nothing to it mate.

 

[Nordin]

Stewart, the thin wires are the prime winding. One of them are the common wire for the prime and the secondary winding.
The common wire should be connected to ground and the other connected to the points.
If both thin wires are connected to the points you newer will have spark.
You can measure the prime and the secondary winding with a VOM.
Prime winding should read about 0,5-1,0 Ohm
Secondary winding should read about 5,5-7 kOhm.
Best is as racerone says, check the coils with a spark tester.
They should jump at least 3/8 in spark in atmosphere.

 

[Stewart Orchard]

I tested from the spark plug wire to each small wire. Both read 7kOhm. I don't see anywhere to connect wires other than the points. Does anyone have a picture of what I should be seeing?

 

[Nordin]

There are four or five (I do not remember) screws that hold the magneto stator ring to the stator plate (timing plate).
One of those has a wire for grounding the stator plate to the block at the fuel pump.
Use one of those screws that hold the magneto stator ring to the stator plate or use the screw that hold the condenser to the plate to ground the coil prime and secondary winding
I have several of those timing plates for the 20Hp in my stock of spare parts BUT they are not so easy to pick out and I do not have photographic memory.
I am pretty sure there are screws for the grounding, but I can not tell you exactly where at the timing plate.

 

[Stewart Orchard]

Here are some pics. One of the ignition setup. The two others are the reading from the spark plug wire to each of the two red wires on the back side of the coil. It appears to me that the points themselves are grounded to the plate, which is grounded to the fuel pump by a wire.

I have my new condensers and still no spark. I have place the voltmeter at the end of the spark plug wire and grounded the other lead. When the flywheel is spun I get an OL on the meter volts DC, but no spark. Also tried new plugs and a spark indicator, nothing.

How do I test the coils?

 

[Nordin]

Stewart, I will take a look tonight under the flywheel of one of my 20Hp Chrysler an see where the grounding of the coil is situated.
As I mentioned before both thin wires from the coil can not be attached to the points terminal. One should be and the other should be grounded.
Otherwise you do not get any spark.

 

[Stewart Orchard]

I had purchased this engine from craigslist for $75. At this price it was as is. I brought it home and check the compression, spark, etc. I have no spark but am at a stand. I decided to check the gearbox while I ponder the spark issue. I found no impeller in the water pump. Welds around the prop hub for some reason. No oil in the gearbox. I assume, by the very loose fasteners, that the previous owner had tried all I have and failed, plus tried to fix some issue with the gearbox, probably seals. Is it worth trying to get running? It still has excellent compression and is cosmetically pretty nice.

 

[racerone]

Nothing but a parts motor in my opinion.-----But in my area there are so many good project motors that I do not need one of those.

 

[Stewart Orchard]

Problem solved! The top wire off the coil should have been connected to the top of the metal surrounding the coils. Good strong spark. I think I will invest in an impeller and give her a run. Anyone know the part number? Googling this engine doe not give me confidence in getting the right part.

 

[Nordin]

Impeller OEM partnr. is 436065 (new F436065 or F436065-2) and Mercury dealer will have it.
Aftermarket Sierra 18-8903 and many website will have it.

 

[topgun3690]

I had purchased this engine from craigslist for $75. At this price it was as is. I brought it home and check the compression, spark, etc. I have no spark but am at a stand. I decided to check the gearbox while I ponder the spark issue. I found no impeller in the water pump. Welds around the prop hub for some reason. No oil in the gearbox. I assume, by the very loose fasteners, that the previous owner had tried all I have and failed, plus tried to fix some issue with the gearbox, probably seals. Is it worth trying to get running? It still has excellent compression and is cosmetically pretty nice.

That is some "Fugly" welding for sure.....if you're not worried about cosmetics it might be ok? IDK

 

[racerone]

When those have water in the gearcase in freezing climates you get ice.----There is a snap ring in a groove and the pressure pops the housing right there because it is the weakest point.-----New / used gearcase is the fix.

 

[Stewart Orchard]

Thanks everyone. That's the impeller number I thought but could not be sure. Oil is holding in the gearcase. Gears engage properly and turn with no grinding. Ill put an impeller in and see what happens.