Thread Tools Search this Thread
Old 14 May 2012, 17:01   #1
Country: Greece
Length: 7m +
Join Date: May 2008
Posts: 16
tachometer issues

honda 225 and my tachometer got crazy.. always showing more revs than the actuall revs of the engine ...
any ideas if is something to fix or just neeed a new one?

cuteshark is offline   Reply With Quote
Old 15 May 2012, 02:59   #2
Country: UK - Scotland
Boat name: Wildheart
Make: Humber/Delta Seasafe
Length: 5m +
Engine: Merc 60 Clamshell
MMSI: 235068449
Join Date: Apr 2007
Posts: 4,539
If you had said you had just fitted a new one I would have guessed that the pole switch was in the wrong place. I;ve not heard of the switch randomly changing, but you may have a fluky vibration that has moved it.

The tacho counts alternator pulses. if you have more poles in your alternator than the tacho thinks, it will for example see 4 pulses per rev instead of 2. If your switch is set to "4" it will be expecting 4 pulses per rev. If you have a 6 pole alternator it will in reality see 6 pulses per rev. so the tacho will think the engine is going 50% faster than it really is. The only way the tacho knows how many pulses it should see is by that switch on the back.

Did it just randomly start doing this, or have you been mucking about?
9D280 is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 14:13.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.