| Onan choke pull-off repair [message #363721] |
Mon, 26 April 2021 11:03  |
boybach
Messages: 566
Registered: December 2020
Location: Vancouver Island
Karma: 4
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My replacement choke mechanism was very tired and the wiring from the solenoid under the control board had problems in the past also. Basically what I had was not reliable, the pull off coil connection was intermittent due to the PO had using a very iffy method to repair the wire.
When I by-passed the original wire, the choke engaged and disengaged as to spec, but even after running a new wire back to the starter box, operation was sketchy and intermittent.
Removed choke assembly and took it to pieces. Bent back the metal tabs and took out the coil assy. Connection from coil to wire connector was severed and connection under the brass connector very oxidized.
Removed remnant of coil wire from under the brass connector, about 1" was serviceable after cleaning. The coil winding was severed very close to the cover (ground!) and the insulating sleeve and insulation in general didn't look that reliable either. I decided to remove all the old insulation on the brass plate (black insulation material) and coil top surface (paper) and start over.
Pulling the end of the winding up slightly, I was able to solder the broken 1" piece back to the winding and using a sleeve made from a regular bit of spare wire, slipped it over the joint insulating it from the case.
Next I cut a circular scrap piece of thin plastic and placed it on top of the coil.
The most time consuming part of the job was recreating the brass plate insulator - with it's corresponding connector it basically looks like a table tennis racket with a fat handle. Other than insulating the connector plate from the internals it also does double-duty preventing side to side movement within the case.
Before repair, the screw connector at the choke (tennis bat handle) could be wiggled slightly up and down. From what I could see in the Sissons choke mechanism, internal tolerances were not that great and possibility of a dead short quite possible.
Initially I'd planned on using some thin plastic as the brass plate insulator but realized that wasn't going to do anything to keep it from rotating, i.e. connector moving up and down so I decided to use a more rigid and thicker plastic to make the piece. There are three tangs on the plate that pass through the insulator holding it in position.
A CD case is what I used and cut (melted) it to shape using my tiniest soldering tip. I made it a tight fit into the coil housing and reassembled the coil assemble back to the actuating housing.
Finally I cleaned and fluxed the plate at the connector and soldered the 1" coil winding end under and to the screw body.
We will see if it works today! Wish me luck!!
Larry
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
[Updated on: Mon, 26 April 2021 11:07] Report message to a moderator |
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| Re: Onan choke pull-off repair [message #363722 is a reply to message #363721] |
Mon, 26 April 2021 12:53  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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It’s more of a pull ON. Coil gets power when cranking, always. The thermal spring just keeps it from actuating the choke when hot.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Onan choke pull-off repair [message #363723 is a reply to message #363722] |
Mon, 26 April 2021 14:17 |
boybach
Messages: 566
Registered: December 2020
Location: Vancouver Island
Karma: 4
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Senior Member |
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JohnL455 wrote on Mon, 26 April 2021 10:53It’s more of a pull ON. Coil gets power when cranking, always. The thermal spring just keeps it from actuating the choke when hot.
Potato, potahto.  I know how it works and it does indeed now work reliably with my rebuild so all good. Next jobs, couple of leaks in fan housings, have the stuff to seal it, just waiting for the April showers to give way to May flowers.
Larry
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
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