AboutEric A. Jones Expertise Lawnmower Repair . Certified Master Service Technician from B&S. Have 13 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.
Experience Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. I received a scholarship from the Air Force and am currently pursuing another degree.
Question Subject - Start Problem
Item - Generac 5kw generator with BandS 10hp 19G412 motor with pull start.
Problem -
1. Motor will not start when cold, with or without choke.
2. Motor will start first pull with a one half second shot of pressurized Prestone motor start fluid in the carb.
3. Motor will start first pull up to two hours after shut off after running until warmed up.
Particulars -
1. Generator is about two years old.
2. Generator has only about 20 hours of total run time.
3. New spark plug (.030 gap)
4. New Gas (regular unledded)
5. New oil (30wt)
6. Choke is working OK.
7. BandS dealer checked and adjusted vlaves, checked spark, both OK.
8. When it is running with no load, it rust uneven. It has a slight variation in speed that gos away when it is choked about half way.
Question
What is the problem and how do I fix it?
Ron Swaim
Answer You may want to inspect the carburetor. The generator should start with the choke. Either there is a gasket leaking preventing the enrichened choke mix or the carburetor is restricted not supplying enough fuel.
As for the surging, many Gerneracs have this sypmtom. The 2 primary causes is a weak governor spring or incorrect governed RPM. Most Generacs need to be set at 3600 +/- 100 rpm. If they still surge after taching the engine then we normally replace the spring and check the engine rpm again.
If it still surges with a new spring then I'd inspect the engine mounts. Many Generacs use rubber mounts to dampen vibration. We've found that sometimes the mounts soften or become weak over time causing the engine to vibrate too much which results in engine speed surging. Generators are very sensitive vibration and engine loading, which you want, but this can cause minor surging that you described. The surging may disappear when the choke is applied because you change the engine rpm just a slight amount.
Let me know what you find. I haven't seen very many Generacs since leaving Hawaii but they were very popular over there.
Eric
