First Tohatsu motor 9.9HP

andreipou

Petty Officer 2nd Class
Joined
Nov 26, 2008
Messages
176
Hi,
I have my first Tohatsu motor on hands and trying to find some basic info.
Looks like year is not an easy task to determine.
Can anyone help help?

Also, on one parts site shows spark plugs for M9.9B2 as B7HS-10, another one BR7HS-10 and the PDF manual I found on the Web shows BR6HS. What is the correct one? I always try to use only original plugs for the motor...
Thanks.
 

Attachments

  • 20210702_180648.jpg
    20210702_180648.jpg
    3.1 MB · Views: 5
  • 20210702_180643.jpg
    20210702_180643.jpg
    4 MB · Views: 5

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
11,591
As per Paul's saying : year it's irrelevant, model says it's all, which 9.9 model is it ? Can use any of the 2 first mentioned NGK spark plugs, the R is with an internal resistor, good if having electronic toys aboard, gap them tight to 1.0 mm. The 6 plug is too hot, stay away from those...

Depending on model can convert a 9.9 into a 15 HP for peanuts costs...

Happt Boating
 
Last edited:

andreipou

Petty Officer 2nd Class
Joined
Nov 26, 2008
Messages
176
I thought that M9.9B2 is the model. Is not it?
Manual that I found is for M9.9C2.
I guess it is not good.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
11,591
I thought that M9.9B2 is the model. Is not it?
Manual that I found is for M9.9C2.
I guess it is not good.
Check if the motor has a sticker seen side of the pan, if so will tell the exact model. The M9.9B2 is the previous version to the M9.9C2 and the M9.9D2 it's the latest version under current fabrication. Same applies for spark plugs as mentioned previously...

Happy Boating
 

andreipou

Petty Officer 2nd Class
Joined
Nov 26, 2008
Messages
176
Check if the motor has a sticker seen side of the pan, if so will tell the exact model. The M9.9B2 is the previous version to the M9.9C2 and the M9.9D2 it's the latest version under current fabrication. Same applies for spark plugs as mentioned previously...

Happy Boating
The sticker on pic#2?
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
11,591
Sorry just saw the posted pics, the C2 version it's much better than the previous B2 one. What other issue would you like to know about ?

Happy Boating
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,242
Yep. No carb kits anymore, but wp kits are available. Is there a problem with this old obsolete motor?
 

andreipou

Petty Officer 2nd Class
Joined
Nov 26, 2008
Messages
176
I got it very cheap because owner stripped one of the plug's thread and did not want to bother with it.
I put thread inserts on two of my OMC motors, so I know how to fix it, but I do not think I have to do it because I run thread chaser on it and plug sits tight now.
The compression is 140 and 138.
I am just waiting on new plugs and fuel connector to try it.
I had about dozen OMC, 1 mercury and 2 Mariners(Yamaha) motors so far.
Will see if I can deal with Tohatsu now.
I was told it was running, but who knows.
With old motors it is always a lottery.
The parts diagrams are clumsy and not all parts available.
Also, I found service manuals for C2, D2, but not for B2 so far.
I would need to find it to get to basic tune up procedures, etc.

Tohatsu website response was that this one was made between 1986 and 1991. It is unusual for me not to be able to determine even the exact year of the motor...
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,242
Year is irrelevant; Model is everything. That model is covered in the combined 1 and 2 cylinder Tohatsu Factory service manual.
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,242
No, the Tohatsu Factory service manuals are copyrighted, so no online access.

SERVICE MANUAL : 1 & 2 CYLINDER 2-STROKES​

a

Description
Covers all 1 & 2 cylinder 2-stroke models.
Part #: 003-21035-1
List Price (MSRP): $50.00
 

andreipou

Petty Officer 2nd Class
Joined
Nov 26, 2008
Messages
176
Finally got the plugs and fuel connector.
Gave a few pulls,: no signs of life.
Pulled out sparks and grounded them, pulled cord - no sparks.
Needs new coil?
Boats.net shows them still available for $52.
What else could it be?

Still waiting on service manual to be delivered.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
11,591
Finally got the plugs and fuel connector.
Gave a few pulls,: no signs of life.
Pulled out sparks and grounded them, pulled cord - no sparks.
Needs new coil?
Boats.net shows them still available for $52.
What else could it be?

Still waiting on service manual to be delivered.
Was the red cord attached to the switch ? If so need to troubleshoot the exciter coil located under the flywheel and the CDI if good or shot...

Happy Boating
 

andreipou

Petty Officer 2nd Class
Joined
Nov 26, 2008
Messages
176
Was the red cord attached to the switch ? If so need to troubleshoot the exciter coil located under the flywheel and the CDI if good or shot...

Happy Boating
Not sure what red cord and switch...

Is there a way to test the ignition coil with Ohm meter before I buy new one?
I have done it wit OMC coils.
Still do not have the manual for this motor...
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
11,591
Not familiar with an 9.9B2 motor, if the ohm specs of the 9.9D apply are : Exciter Coil : 168-253 Ohms, Pulser Coil : 30-46 Ohms.

Happy Boating
 

andreipou

Petty Officer 2nd Class
Joined
Nov 26, 2008
Messages
176
Finally got the manual that looks exactly the same, but it only mentions C and D models.
Can I go by that for B?
 

Attachments

  • thumbnail.jpg
    thumbnail.jpg
    65.9 KB · Views: 1
Top