Hercules Engine News

Including Economy, Arco, Jaeger & Thermoil

| February/March 1995

20601 Old State Rood Haubstadt, Indiana 47639

Once the cam gear and exhaust valve adjustments have been properly set, the third step, timing the ignition, can he made. Although there are several different ignition systems used on Hercules built engines, in this article the Webster system using the M, K and L magnetos will be discussed. The instructions given here are for engines to be run at or near rated speeds and that are intended to pull a load. It should be noted that if parts are badly worn or other repairs poorly made, the necessary adjustments may be hard to make and maintain. Further, these adjustment instructions can be used on other brands of engines once a timing reference point has been determined.

Some engine instruction manuals give the timing recommendations in terms of degree of spark advance ahead of inner dead center. Jumbo literature mentions eight degrees of advance for each 100 RPM; i.e. 40 degrees for 500 RPM and 28 degrees for 350 RPM. Racine-Sattley literature lists 35 degrees for the 1 HP graduated down to 15 degrees for the 15 HP. These recommended advances appear to be greater than those obtained when properly setting the advance for Hercules built engines. The degree of timing advance depends on a number of factors, including RPM, stroke length, flywheel weight and flywheel diameter.

In the next article the discussion will cover timing and other adjustments for slow running show engines.


Gas Engine Magazine A_M 16Gas Engine Magazine is your best source for tractor and stationary gas engine information.  Subscribe and connect with more than 23,000 other gas engine collectors and build your knowledge, share your passion and search for parts, in the publication written by and for gas engine enthusiasts! Gas Engine Magazine brings you: restoration stories, company histories, and technical advice. Plus our Flywheel Forum column helps answer your engine inquiries!

Be sure to take advantage of the Square Deal Subscription Program.

  • No Missed Issues.

  • No Renewal Notices.

  • No Additional Cost.

The Square Deal Subscription Program is designed as a paperless transaction with automatic renewals at a preferred low rate.   With advanced electronic notification, a 100% satisfaction guarantee and an easy opt-out plan, the Square Deal Subscription Program is the best value, risk free, eco-friendliest way to subscribe.

Facebook YouTube