40EL75 Rebirth

[flyingscott]

Then the screw that holds the plug wire is just for show?

If you look at the replacement coils for the low tension magneto they come with the wires installed and molded in. Not supposed to be replaceable. How are you going to hold the wire onto the post tight when everything that supports it is ground away.

 

[hardwater fisherman]

If those are the original coils you cannot replace the plug wire on them as they are part of the coil assembly. The newer style coils have replaceable wires.

Are you re thinking this then? EDIT Or are you saying that neither new or old coils can have the plug wires replaced? BTW nothing was ground away I just broke it off so he could see the pin.

 

[flyingscott]

The low tension magneto coils are not designed to have the wires replaced on the original or replacements. The newer style CDI coils can have the wires replaced because they build a post into the coil for the wire. You broke your your coil that is why you can see the post, on an unbroken coil the wire is epoxied in so it cannot be removed. Look up the replacement coil for the motor and you will see it comes with the wire molded in, it's not hard.

 

[hardwater fisherman]

I know and respect that you are much more experienced with this then me. The fact is I chased a no spark on the bottom cylinder of a 1976 40hp and I gave up on it for almost 1 year. And now it is running good again. I think it was the plug wires.

 

[hardwater fisherman]

But I bought new coils and I had to install the plug wires. Check the part number 502881.

 

[flyingscott]

But I bought new coils and I had to install the plug wires. Check the part number 502881.

That is a factory coil when i replace coils with those, I epoxy those in because they tend to work their way loose.

 

[hardwater fisherman]

No disrespect but you went from the factory coils being fixed. And then the replacement coils to being fixed. And then both being fixed. And then you said you epoxy those factory coils. I give up you win.

 

[flyingscott]

No disrespect but you went from the factory coils being fixed. And then the replacement coils to being fixed. And then both being fixed. And then you said you epoxy those factory coils. I give up you win.

What are you talking about I said the wires are epoxied in. The coil you have is not that old of a part #, the # that preceded it was epoxied in. What do you think is cheaper to make, give you a bunch of parts and let you deal with it, Or put it all together. The coil you bought is not an improvement it's just made cheaper. I have used a couple of those and the wires can work themselves out so I epoxy them. The sierra coil still comes with the wire permanently attached. If you look at the coil for the CDI ignition motors they have a boot at both ends yours does not.

 

[hardwater fisherman]

I really dont know but when I saw that I was able to screw the wires in and out. That was good enough for me. And I thought why make them like that if not for changing the plug wire?

 

[hardwater fisherman]

If those are the original coils you cannot replace the plug wire on them as they are part of the coil assembly. The newer style coils have replaceable wires.

Here is where you said the factory coils have fixed wires. And you said the newer coils can have replaced wires.

 

[flyingscott]

Maybe you should read my other posts where I specifically mentioned the low tension magneto coils do not have replaceable wires if they are original. Or where I mentioned newer style CDI ignition coils that have replaceable wires. And you were the one that said as long as you break the coil the wire is replaceable and then all of a sudden you have one that can be replaced. I am done with this post. You can argue this all you want it won't be with me.


I will leave you with one question. Why were the wires epoxied in for so long when they had a screw in stud? Then all of a sudden they just decide to just give you a bunch of parts?

 

[hardwater fisherman]

I explained that I broke a DEAD coil to show that there was a screw to thread the plug wire on. You were the one all over the place saying not replaceable. And then replaceable with epoxy. None of my plug wires new or old were epoxied.

 

[hardwater fisherman]

YOU WIN. I have no spark on 3 of my coils because I replaced the plug wires.

 

[hardwater fisherman]

If those are the original coils you cannot replace the plug wire on them as they are part of the coil assembly. The newer style coils have replaceable wires.

If you say the original coils can not have the plug wires replaced. Then this must be a very old replacement coil then. But I think this is the coil that was on the motor when it left the factory. As you can see there is no epoxy and there never was. I can simply turn and pull it out. And push and turn it back in. I consider that as a coil that has replaceable plug wires. BTW This coil was taken off my motor. And it functions.Also I have a 1975 40hp johnson I bought for parts and it has the same coils, So if what you say is true then all 4 coils failed early on in there life and were replaced with identical replacements.

 

[oldrem]

Does anyone have the actual original cylinder bore dia for this model? All I'm finding is 3.18, but thinking it may have been 3.1875" like most others??

 

[hardwater fisherman]

My service manual says 3-3/16" bore x 2-3/4" stroke. 3.1875" diameter rings. 43.9 cubic inches.

 

[hardwater fisherman]

Speaking of my service manual. I guess it is also wrong when it says install the ignition coils onto the head and then connect high tension leads to the coils.

 

[oldrem]

I'm feeling a whole lot better about this motor now. One of my son-in-laws rebuilds a lot of motors and let me borrow his good compression tester. I'm pleased with the new corrected readings of 110 and 111. I should have read the reviews on the HF one before I bought it. Many said it reads as much as 30psi low. In my case it was 22 and just about gave me ulcers. lol

Now on to pull the head and do a good job of carbon removal on the cylinders, but that's for another weekend. Getting my parts together to replace solenoid, coils, condensers and points before I ever try firing it.

 

[hardwater fisherman]

I think my compression tester probably reads a little bit high. When I first tested it years ago I had 135psi on each. And the top stayed that way but the bottom slipped slowly down below 120 psi. I changed the head gasket and resurfaced the head and now I have 130psi on each, When you get it running the compression might come up. And just a heads up for when you get it running and you will need to replace the water pump impeller. The impellers have not been made for some years and the last one I found cost me almost 80 dollars Canadian with exchange and shipping. I have been checking and I have not been able to find another. There is a kit for sale that has an impeller and housing and also the wear plate. For 75 US dollars but I could only see one in stock at this moment. There is also an upgrade kit that was used on 40hp commercial models built during the 80s. It retails for 100 US dollars. But after when you need to change just the impeller they can be bought fairly cheap. If you are interested the part number is 391741.

 

[oldrem]

Thanks for the heads up. I knew it would need replacing, but was going to wait to look. Now I've started looking hard. I've located the upgrade kit from a couple sources for around $60, and have a possible lead on an original NOS impeller for $35. If the NOS falls through, I'll do the upgrade unless you think it's going to do a better job of cooling?