Faria Beede Tachometer reading high intermittently

[ratdude747]

Yesterday I had an odd fault with my Faria Beede tachometer I installed in my boat last year (for what it's worth, it's Faria Beede F33004).

On startup it was reading way, way higher than normal (showing I was idling at 3000RPM!). After some testing to confirm it was a gauge issue, I thumped on the gage with my thumb and it started reading correctly again. It acted up one more time, but behaved after a bump or two.

What would cause that? Solder joint failure inside the tach? Faulty engine selector (pulse count scaling) switch? I do electronics work on the side and (to a lesser degree) as part of my day job, so electronics repair is up my alley. I can get a new one for about $100 but I am both cheap and not a fan of replacing things I have the ability to fix correctly. But I also know it may be a sealed unit?

My instrument cluster is an absolute pain to remove (steering gear has to come apart first, which is not a fun job!)... so unless I put it off to the offseason (likely will ), I'd like to have a plan ahead of time.

I've read of others having this issue but didn't find any resolutions.

 

[Scott Danforth]

plug and unplug the connectors on the back of the switch once or twice.

then loosen and tighten the ground wire on the terminal block

then switch the little selector switch on the back of the tach.

should be good to go for another year or two. can spray the back of the tach with marine electrical varnish

micro-corrosion on boats is just part of the boating exerience.

 

[ratdude747]

plug and unplug the connectors on the back of the switch once or twice.

then loosen and tighten the ground wire on the terminal block

then switch the little selector switch on the back of the tach.

should be good to go for another year or two. can spray the back of the tach with marine electrical varnish

micro-corrosion on boats is just part of the boating exerience.

Back of what switch? By "engine selector" I meant the little switch on the tach for selecting how many cylinders the engine has (how many ignition pulses per rotation).

All my connections are point-to-point... no terminal block to speak of:

Unless you're referring to the transom area terminals for the shift kill switch?

 

[Scott Danforth]

yes, the little cheesy selector switch. change it from one end to the other, then set it back. that wipes the contacts a bit, cleaning them to get a better contact (common marine tach issue)

since your tach looks to have ring terminals, loosen those and re-tighten.

 

[bajaman123]

I've found that it's simply easiest to just give them the 'thunk' every now and then...every Faria tach I have ever seen did this at one point or another.