Reply
 
Thread Tools Search this Thread
 
Old 10 September 2014, 07:09   #1
Member
 
Country: Australia
Town: Australia
Boat name: none
Make: JP Marine 3.8 Patrol
Length: 3m +
Engine: Tohatsu 18hp 2stroke
Join Date: May 2013
Posts: 69
Tiny Tach on Tohatsu 18 hp

I just bought a Tiny Tach for my Tohatsu 18 hp 2 stroke. Does anyone know what the setting sould be ie. 360 deg, 180 deg or some other setting.
The manufacture recommends 360 deg. I find that the revs shown are too high. So I have selected 180 deg.
__________________
seasdes is offline   Reply With Quote
Old 12 September 2014, 00:30   #2
Member
 
Country: Australia
Town: Australia
Boat name: none
Make: JP Marine 3.8 Patrol
Length: 3m +
Engine: Tohatsu 18hp 2stroke
Join Date: May 2013
Posts: 69
Ok. Looks like nobody uses the Tiny Tach. So does anybody know what rpm the 18 hp Tohatsu idles at. This will help me set the Tiny Tach correctly
__________________
seasdes is offline   Reply With Quote
Old 12 September 2014, 01:22   #3
Member
 
dave3235's Avatar
 
Country: UK - England
Town: Bristol
Boat name: Salty Cheeks
Make: Honwave
Length: 3m +
Engine: 20hp 2stroke Mariner
Join Date: Mar 2014
Posts: 485
Quote:
Originally Posted by seasdes View Post
Ok. Looks like nobody uses the Tiny Tach. So does anybody know what rpm the 18 hp Tohatsu idles at. This will help me set the Tiny Tach correctly
Hi

I would have thought 4500 to 5500 rpm and idle would be 750 to 1000 would be about right.Not 100% on your rev range though.
__________________
dave3235 is offline   Reply With Quote
Old 12 September 2014, 11:29   #4
Member
 
Country: Australia
Town: Australia
Boat name: none
Make: JP Marine 3.8 Patrol
Length: 3m +
Engine: Tohatsu 18hp 2stroke
Join Date: May 2013
Posts: 69
After all else fails, read the manual. The manual advises idling revs while stationary to be 950 rpm and 800 rpm while in gear.
Now I wish I new someone with this tach and an 18 hp Tohatsu. I am getting different advice on settings from people who should know.
__________________
seasdes is offline   Reply With Quote
Old 12 September 2014, 14:09   #5
Member
 
chipko's Avatar
 
Country: UK - England
Town: Up North and right a bit
Make: XS500/Merc340/Bic245
Length: 5m +
Engine: Mar 60/20/3.5/Hon2.3
Join Date: Sep 2013
Posts: 1,055
Tiny Tach on Tohatsu 18 hp

Hi,
The manual for the 9.8 Tohatsu states idle rpm 950 out of gear and 750 in, and 5 - 6000 full throttle range. The 18 is probably similar.
I have a cheapo tach similar to a Tiny Tach and this is set to 02 (once per revolution).
To be honest it's fairly easy to tell if setting is wrong as the revs are either double or half what they should be😎
__________________
chipko is offline   Reply With Quote
Old 12 September 2014, 22:18   #6
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
One of you 2-stroke guys correct me if I'm way off base here - I seem to recall hearing of some 2-strokes set up like this:

I believe you may have a motor that fires every revolution of the crankshaft, but the spark plugs share the same feed (i.e. each plug is firing twice per revolution.)

If that's the case, you'd need to set the TT to 180 degrees (I think.)

jky
__________________
jyasaki is offline   Reply With Quote
Old 13 September 2014, 02:26   #7
Member
 
Country: Australia
Town: Australia
Boat name: none
Make: JP Marine 3.8 Patrol
Length: 3m +
Engine: Tohatsu 18hp 2stroke
Join Date: May 2013
Posts: 69
Yes with the Tohatsu 18 hp 2 stroke I have set the TT to 180 deg. My engine was idling a bit high I think, so I adjusted the idle down a bit. Now using the 180° setting the TT displays engine idling at 950 - 1000 rpm. Sounds about right (I think) but it would be nice if someone with a setup similar to mine could confirm.
__________________
seasdes is offline   Reply With Quote
Old 13 September 2014, 07:09   #8
Member
 
HughN's Avatar
 
Country: UK - England
Town: Littlehampton, W Sx
Length: no boat
MMSI: 235101591
Join Date: Jan 2012
Posts: 732
Quote:
Originally Posted by jyasaki View Post
I believe you may have a motor that fires every revolution of the crankshaft, but the spark plugs share the same feed (i.e. each plug is firing twice per revolution.)
= "Lost spark"
__________________
"Can ye model it? For if ye can, ye understand it, and if ye canna, ye dinna!" - Lord kelvin
HughN is offline   Reply With Quote
Old 13 September 2014, 07:42   #9
Member
 
Roflhat's Avatar
 
Country: UK - Scotland
Town: Isle of Lewis
Boat name: Macleod Special
Make: Ceasar Thundercat
Length: 4m +
Engine: Yamaha 70ces
Join Date: Jul 2010
Posts: 1,190
RIBase
Just try the different settings until it looks right, I've got one on my tohatsu 50 and it works great. can't remember the setting but I just fiddled around until the revs were about right. The other two settings will give completely different revs
__________________
Roflhat is offline   Reply With Quote
Old 13 September 2014, 18:53   #10
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
Quote:
Originally Posted by HughN View Post
= "Lost spark"
I think it was done for simplicity. Didn't have to engineer 2 separate spark circuits.

jky
__________________
jyasaki is offline   Reply With Quote
Reply

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




All times are GMT. The time now is 11:29.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.