Johnson Seahorse TN28 Timing off?

[The Boat House]

Are the points wired to the correct cylinders?
When one set of points open is that piston at
the top of the cylinder?

[mikele86]

It’s deffinitly a spark plug issue… I can’t find the right spark plugs anywhere near me Champion J6J is what is recommended, J6C is a newer replacement , I cant find these either.

I went to autozone and advance auto and picked up 2 different pair of plugs that were cross referenced.. autolites and NGKs… I gapped the NGKs to what’s recommended at .020 and could maybe get a spark once every ten pulls…. with that I got the engine to cough… but these are obviously not the right plugs or maybe I need to gap them differently?

I originally had some AC delco plugs that put out a ton of spark but are not the right size at all

[mikele86]

quote Tubs:

Are the points wired to the correct cylinders?
When one set of points open is that piston at
the top of the cylinder?

I believe so yes

[marvk]

quote mikele86:

I went to autozone and advance auto and picked up 2 different pair of plugs that were cross referenced.. autolites and NGKs… I gapped the NGKs to what’s recommended at .020 and could maybe get a spark once every ten pulls…. with that I got the engine to cough… but these are obviously not the right plugs or maybe I need to gap them differently?

Plugs should be gapped at .030, points are gapped at .020

[Steve A W]

Did You clean the points after you set them?
If they picked up any oil or grease they won’t work properly.
Take a piece of brown grocery bag and wet it with alcohol or
some kind of solvent and drag it between the closed points.
This will degrease them.
We’ll keep shooting suggestions at Ya till we get it running!

Steve A W

Member of the MOB chapter.
I live in Northwest Indiana

[aquasonic]

Mike, It does not sound as though the problem here is the sparkplugs other than an improper gap setting as MarvK stated. You mentioned that you have NGK plugs now. The correct NGK model is the B6S gapped at 0.030".

I read that you have spark on both top and bottom cylinders. How did you test for spark? Did you check it with a neon spark tester or check to see if the spark would jump a 1/4" air gap as FrankR mentioned. With all new ignition components installed correctly you should have a very strong spark. If the spark is not strong, then you should really focus on the ignition components and installation. Clean, properly set points are very important as Steve A W stated.

The primer on these motors is also very important, and if it is not working properly, the motor will be nearly impossible to start cold. When you depress the primer five or six times, does fuel come out of the rotary valve intake on the front of the motor? If no fuel, then that is something to look at. Also, after priming and pulling the motor over a handful of times, if it does not run, then take a look at the sparkplugs. They should be wet with fuel.

Have you done a compression test? That is a good indicator of the internal condition of the motor and is also a good way to check for a blown head gasket. If the compression is good, then there is no reason why this motor can’t be made to run. It’s just a matter of eliminating/ruling out problems one at a time.

[mikele86]

quote aquasonic:

Mike, It does not sound as though the problem here is the sparkplugs other than an improper gap setting as MarvK stated. You mentioned that you have NGK plugs now. The correct NGK model is the B6S gapped at 0.030".

I read that you have spark on both top and bottom cylinders. How did you test for spark? Did you check it with a neon spark tester or check to see if the spark would jump a 1/4" air gap as FrankR mentioned. With all new ignition components installed correctly you should have a very strong spark. If the spark is not strong, then you should really focus on the ignition components and installation. Clean, properly set points are very important as Steve A W stated.

The primer on these motors is also very important, and if it is not working properly, the motor will be nearly impossible to start cold. When you depress the primer five or six times, does fuel come out of the rotary valve intake on the front of the motor? If no fuel, then that is something to look at. Also, after priming and pulling the motor over a handful of times, if it does not run, then take a look at the sparkplugs. They should be wet with fuel.

Have you done a compression test? That is a good indicator of the internal condition of the motor and is also a good way to check for a blown head gasket. If the compression is good, then there is no reason why this motor can’t be made to run. It’s just a matter of eliminating/ruling out problems one at a time.

Picked up the right plugs champion J6C and gapped them at .030… still nothing even with spraying starter fluid in the cylinders. I get great spark when testing them before putting them back in the block. The primer is working great as well, I notice fuel coming out of the rotary valve when pushed. Checked the compression and getting 75-80 per cylinder. I’m going to check the points next. Will update.. Thanks!

[jeff-register]

How about the points cam? Can it be flipped & out of time? Check those new coils as the soldered connection for the high voltage wires or does the 28 take the universal coil?

[mikele86]

quote Jeff Register:

How about the points cam? Can it be flipped & out of time? Check those new coils as the soldered connection for the high voltage wires or does the 28 take the universal coil?

Got new plugs J6C Champions. Set the timing right to gap at .02 when piston is at the top on each cylinder… still nothing. Can’t even get the engine to cough after spraying fluid into both cylinders. It seems to me I’m not getting spark when put back into the cylinder. 😥

Is it possible for the cam to be flipped? I did replace the piston rings, is it possible I could of installed the pistons backwards somehow?

This is starting to drive me nuts 😐

[mikele86]

quote MarvK:

quote mikele86:

I went to autozone and advance auto and picked up 2 different pair of plugs that were cross referenced.. autolites and NGKs… I gapped the NGKs to what’s recommended at .020 and could maybe get a spark once every ten pulls…. with that I got the engine to cough… but these are obviously not the right plugs or maybe I need to gap them differently?

Plugs should be gapped at .030, points are gapped at .020

The same goes for champion J6C?

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