Wise to bypass vacuum switch? (1990 Johnson 200)

27E_20

Seaman
Joined
Jan 17, 2012
Messages
55
Engine: 1990 Johnson 200 (VJ200SLESE)

Last Friday I installed rebuilt carbs and changed out ALL fuel lines on the engine. In the process, I believe I might have pinched or damaged one of the wires on the vacuum switch (fat hands).

I realized this yesterday when I had the boat out on the water (engine was running flawlessly- no more sneezing!), my alarm would intermittently sound as I was bouncing up and down on the water- a kind of flickering, like there was a loose connection. Then as I came off plane to no wake speed the alarm was steady. Engine was peeing water like it should, the water pressure gauge was responding, AND I was still able to get back on plane and run at WOT with the alarm still sounding, so I ruled out the possibility of overheating.

Took the cowl off and wiggled the vacuum switch wires around with engine running and the alarm would cut in and out. Finally got the wires to a sweet spot and threw a ty-wrap around them. Problem solved for now.

Questions:

Manual says the vacuum switch will cause a continuous warning tone if it detects a restriction in the fuel supply system. So Im guessing it lets you know when you’re almost out of gas? Wouldn’t the engine shutting down be enough to tell you? I have two tanks and two functioning fuel gauges. Do I really need a warning tone when Im out of gas? No need to scare the crap out of someone, thinking their engine is about to overheat when really you’re just low on fuel, right? Or is there more to this vacuum switch?

If not essential, is there a way to bypass this switch? Or do I really need to spend $100+ on a new one? The wire is pinched/broken/loose right at the base of the connector – no way to splice or repair it.

Pictures were taken BEFORE I replaced fuel filter/lines etc.

Vacuum Sw_1 (450x800).jpgVacuum Sw_2.jpg
 
Last edited:

schematic

Lieutenant Junior Grade
Joined
Jan 12, 2008
Messages
1,102
Re: Wise to bypass vacuum switch? (1990 Johnson 200)

Manual says the vacuum switch will cause a continuous warning tone if it detects a restriction in the fuel supply system. So Im guessing it lets you know when you’re almost out of gas? Wouldn’t the engine shutting down be enough to tell you? I have two tanks and two functioning fuel gauges. Do I really need a warning tone when Im out of gas? No need to scare the crap out of someone, thinking their engine is about to overheat when really you’re just low on fuel, right? Or is there more to this vacuum switch?

no switch + fuel restriction = possible lean engine = burnt pistons = way more than $100
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: Wise to bypass vacuum switch? (1990 Johnson 200)

Install a new switch. It was put there for a reason.
 

27E_20

Seaman
Joined
Jan 17, 2012
Messages
55
Re: Wise to bypass vacuum switch? (1990 Johnson 200)

Got one on order. Thanks
 
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