Trojan Boat Forum

Another annoying newbie question here guys. When I purchased the 1976 trifly w twin 400s there had been some minor"tampering" by prospective buyers and marina mates etc... (boat was open for years) so when I decided to replace the plug wires I noticed the elect dist caps did not have numbering on them. This was important because the wires that are on there have crazy masking tape lables that do not correspond to the cyl castings. So how can I be certain which goes to which? Refernce marks? Buy a new cap??

The standard rotation engine firing order is 18436572. Number 1 is front opposite the distributor. With the cap off and coil wire removed. Tap the engine over till you are at top dead center on the compression stroke. You can take the #1 plug out and feel air pressure. When the marks on the harmonic balancer line up stop. Wherever your rotor is pointing is #1. The wires go on counter clockwise. It's a bit confusing.

Yup as Reel easy said
Don't rely on the cap being numbered, just start from the beginning.
If you do it the suggested way and you don't like where the rotor is pointing you can pull the distributer out and turn the shaft 180 degrees and put the distributer back in.
The drive in the bottom is like a slot screw driver and can go in in 2 positions

Reverse rotation engine firing order is 12756348. #1 is still in the same place.

Thanks! Its the stbd im working on!

Reel Easy wrote:The standard rotation engine firing order is 18436572.... The wires go on counter clockwise. It's a bit confusing.

Reel Easy wrote:Reverse rotation engine firing order is 12756348. #1 is still in the same place. The distributor rotor turns clockwise

You're right it is a bit confusing but unless I'm forgetting something, as I recall, every counter rotating engine's rotor direction is the same as the direction of the rotor on the standard rotating engine. The direction may change for different models, but I recall the rotor direction being the same for both engine directions. Am I forgetting something?

Big D wrote:

Reel Easy wrote:The standard rotation engine firing order is 18436572.... The wires go on counter clockwise. It's a bit confusing.

Reel Easy wrote:Reverse rotation engine firing order is 12756348. #1 is still in the same place. The distributor rotor turns clockwise

You're right it is a bit confusing but unless I'm forgetting something, as I recall, every counter rotating engine's rotor direction is the same as the direction of the rotor on the standard rotating engine. The direction may change for different models, but I recall the rotor direction being the same for both engine directions. Am I forgetting something?

Nope....both CCW as far as I remember....Mike

You both are correct. I was misinformed on that. My apologies. There is a easy way to find out. Take the cap off and watch it.

Follow up. Sorted out that its the rev rotation on my STBD side (76 trifly) and some evildoer had mixed up the wires as I suspected. Firing order should be 127xxxx8 and it had four wires switched on the second half of the firing series
I added the new wires I bought here and cap and rotor and guess what? No more backfiring ! Runs great.

That's great news. We always like hearing back what fixed the problems.