Mercury Switch

[9D280]

Anyone had issues with their Mercury mercury switch? (as in the switch type that cuts the engine if you tilt it too far / roll the boat over)

I have been getting intrermittent <off-on> hesitations the last couple of trips, all quite random. It feels like the deadman is intermittenltly being "tapped", but not for long enough to actually kill the engine. So, I went through tbe whole loom looking for loose connections and chaffed insulation (possible shorts). Found absolutely nothing of note.

I then thought to look at the mercury switch. It was nicely open circuit (engine was down).
I unscrewed it, and put the meter in continuity mode across the terminals & gave it a gentle shake. No surprise -I got a beep. I then started the car & held it at the correct angle against the cyl head (to simulate engine vibrations) and got some random hoarse beeps out the meter. Looks like the vibrations are churning the mercury inside the switch around enough to cause it to short briefly.

- Has anyone else found this switch causing problems?
- Is there a new eco friendly mechanical version?

I've disconnected it to see if it improves the running, but will be a while before I can get out to test again.

[nugent]

Originally Posted by 9D280

Anyone had issues with their Mercury mercury switch? (as in the switch type that cuts the engine if you tilt it too far / roll the boat over)

I have been getting intrermittent <off-on> hesitations the last couple of trips, all quite random. It feels like the deadman is intermittenltly being "tapped", but not for long enough to actually kill the engine. So, I went through tbe whole loom looking for loose connections and chaffed insulation (possible shorts). Found absolutely nothing of note.

I then thought to look at the mercury switch. It was nicely open circuit (engine was down).
I unscrewed it, and put the meter in continuity mode across the terminals & gave it a gentle shake. No surprise -I got a beep. I then started the car & held it at the correct angle against the cyl head (to simulate engine vibrations) and got some random hoarse beeps out the meter. Looks like the vibrations are churning the mercury inside the switch around enough to cause it to short briefly.

- Has anyone else found this switch causing problems?
- Is there a new eco friendly mechanical version?

I've disconnected it to see if it improves the running, but will be a while before I can get out to test again.

Very prone for playing up, hence not fitted to later engines, cut wire and disuse it,

[9D280]

You have confirmed my suspicions! Thanks.