Tachometer reading double

[brook]

I have a 2006 Sea-Doo Challenger 180 that suddenly started having tachometer issues. I’m reading at least double the correct RPM. Under throttle the needle maxes out, the alarm sounds with the ‘check engine’ light comes on. I tried taking the grey wire off of the tach to disable it thinking it may be faulty but the alarm and check engine light are still triggered so I’m assuming it’s not the tach itself. I’m at a loss at what to look for. Any ideas are greatly appreciated!

 

[10forty2]

Does she seem to be running good and adequate speed for throttle? You may be cavitating slightly and not pumping the water through as efficiently, letting the engine rpms go crazy while not actually moving the boat through the water.

 

[brook]

Does she seem to be running good and adequate speed for throttle? You may be cavitating slightly and not pumping the water through as efficiently, letting the engine rpms go crazy while not actually moving the boat through the water.

Thanks for the reply. She’s running perfectly. Engine sounds great. Just came from an afternoon of wake-boarding. Other than the tach buried and the check engine beeping every few min you’ve never know anything was wrong. I’m sure it’s a false reading but I have no idea why.

 

[brook]

Anyone else with any thoughts on what to look for? She’s still running beautifully but the alarms are driving me crazy!!!

 

[10forty2]

Just for elimination purposes, disconnect the negative battery cable, leave it disconnected for 30 minutes and then re-attach it. The ECM may just need re-setting.

 

[brook]

Thanks @10forty2 Still same problem. Spoke to a jet boat mechanic who said he’d bet it was an electrical ground issue with a ‘good luck finding that...’