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>Is your Atomic 4 way too hard to get into forward gear or is the forward gear slipping?

Introducing the Indigo Electronics Atomic 4 "1/2 Notch Lock"



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Difficulty getting your Atomic 4 into Forward gear can be especially frustrating if your gear shifter is mounted on the wheel steering pedestal. This is a quite common issue that owners have with the Atomic 4 and until now, there has not been an easy solution to that problem. The issue arises in what is known as the adjusting collar for the Forward clutch in the reversing gear of the engine. As built, there are 15 notches in that collar and you're only able to adjust the clutch a minimum of one notch at a time. It turns out that one notch quite often is too much and this is demonstrated by the fact that the very latest Atomic 4s that were built had a different adjusting collar with almost half again as many notches (21) thus giving finer adjustment. Below is an image of the original Locking Pin which locks the adjusting collar in position once it has been adjusted.


Indigo Design

Meet the Indigo "1/2 Notch Lock" kit. Quite simply, the installation of this lock allows you to make a 1/2 notch adjustment to the position of the Forward adjusting collar. Shown below is an image of the new Indigo retaining lock. If you have reasonable access to the reversing gear inspection cover on the output end of the engine, installation of this new lock is a simple matter of removing the existing retaining pin and lock washer; rotating the adjusting collar either 1/2 notch CW to tighten or CCW to loosen; and installing a special stepped stud, flat washer, lock washer, and nut. It's that simple.

What to expect?

If your Atomic 4 takes an unreasonable amount of force on the shift lever to get it into forward gear, you will want to try turning the adjusting collar 1/2 notch in the CCW direction and then install the Indigo lock to maintain that position. Shifting into Forward should be significantly easier after this adjustment. You will want to verify that the Forward clutch will not slip when you accelerate your Atomic 4 as fast as possible in Forward gear. If it does slip, you will have to go back to the original position of the adjusting collar and then re-install the original retaining pin and lock washer.

If your Atomic 4 is slipping when in forward, that is the engines is making lots of RPMs but the prop is not turning as fast causing the boat to move more slowly than it should, then you will want to try turning the adjusting collar 1/2 notch in the CW direction and then install the Indigo lock to maintain that position. Shifting into forward should be somewhat more difficult after this adjustment. You will want to verify that the Forward clutch has stopped slipping when you accelerate your Atomic as fast as possible 4 in Forward gear. If it still slips, you will want to try turning the adjusting collar an additional 1/2 notch in the CW direction and then re-install the original retaining pin and lock washer. Shifting into Forward should be somewhat more difficult yet after this adjustment. You will want to again verify that the Forward clutch has stopped slipping when you accelerate your Atomic 4 as fast as possible in Forward gear.

  • Easy 30 minute, "bolt on" installation, all necessary components included.
  • All pieces except the stud are magnetic for possible retrieval from sump if dropped.

Download "1/2 Notch Lock" Installation Instructions

Send your questions or comments to me at thomas.stevens@cox.net

Call today for Credit Card orders or send check/money order to:

Indigo Electronics, Inc.

105 Pipe Kiln Court
Williamsburg, VA 23185

Order Today. You never knew sailing could be so much fun!
1-800-428-8569 toll free
or 757-593-8569



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