General help regarding a 2006 Tohatsu M25C3

Branchtree

Cadet
Joined
Jul 2, 2020
Messages
18
Hi.

I was "recently" active in this topic regarding my 9.9/15 and 18 problems and for this year I decided to go bigger.

I bought a 2006 M25C3 which I need some guidance on. The best would be to find a workshop/service manual but I can't find one anywhere. The only PDFs I found are newer tohatsu 2-stroke manuals from tohatsu themselves but I'm guessing that they are not the same as a 2006 one and it doesn't explain service more deeply.

Anyway, I'll attach some pictures to highlight some of my questions.

1; I've done the basic maintenance but it seems that I'm getting water in the gear oil, see attached pictures.
I changed the oil and put the outboard in the water (idling in neutral and in gear) for 30 minutes and drained it again. This is the oil you are seeing in the pictures.
I'm going to head off to my local tohatsu dealer and order some parts for this.

2; This picture shows the butterfly at WOT. It's surprisingly nowhere near 90 degrees open?
Is this something about the 25hp one and the 30 (I've read in this forum that the difference is a carb gasket + timing though)?

3; At idle the screw is not touching the stop? That's an easy job if I know where is should be.
Idle is at 840-900 which seems ok according to the newer tohatsu manual.

4; Another picture of idle

5; Picture of WOT and not touching the stop again. Did someone just move these back because of laziness ?

6; Another picture of WOT


I can manage to fix all these problems if I just can find a service manual :)
 

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pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,509
Yes to upgrade a 25 to a 30 you reset the WOT to full and advance timing.
346873217M​
LOWER UNIT GASKET SET​
$24.73​
 

Branchtree

Cadet
Joined
Jul 2, 2020
Messages
18
Yes to upgrade a 25 to a 30 you reset the WOT to full and advance timing.
346873217M​
LOWER UNIT GASKET SET​
$24.73​
Hi.

I have no need to upgrade to 30 at the moment. That's maybe something I might consider later if needed.

But the small butterfly opening at WOT is normal for the 25?

When I converted my old 9.9 to 15 the difference wasn't that big.
 

Branchtree

Cadet
Joined
Jul 2, 2020
Messages
18
Next problem.

I changed all seals in the lower unit, assembled everything and went to start it in the barrel.
Strangley it started in gear.

Sure, a lot of parts kind of fell out when I half-stripped the lower unit but there aren't that many loose parts.

The shift rod can't be adjusted as far as I know (no extra holes at the connection between upper and lower unit).

I can't pull the starter in forward or reverse but it's possible in neutral with a spinning shaft (anti clockwise when looking at the motor from the steering position).

I can spin the shaft anti clockwise in neutral (with a clonk as the teeth/engage teeth are skipping) and spinning it clockwise the motor wants to cycle.

I went through the service manual and parts list and found that a steel ball (no21) should be behind the clutch push rod. I can't find it so that could be a solution.

I don't have the spacer (no 4) either but that item seems to be a "use if necessary" ( noted with "AR" in parts list').
EDIT; Looking at a different blueprint it seems like that spacer is between the gearset and bearing and therefor I don't see it.

I don't trust the parts list to a 100% but am I on to something here?
 

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Branchtree

Cadet
Joined
Jul 2, 2020
Messages
18
You definitely need the ball.
Yep!
Definitely a rookie mistake. Have o idea where the ball went, propably under the porch......
I have never taken apart a lower case so forgive my ignorance.

Bought the ball and installed everything, works perfect and no water intrusion.


Now, I read the service manual (got one from my local dealer) and began to adjust timing, idle etc.

It says that the M25C3 should have 25 degrees of timing but when I search this forum it says 20?
I've added some pictures.

The pictures are after I tried to set the ignition correct according to the service manual.
This opened the butterfly to 100% though.

Is 4 degress ATDC at idle? The servide manual confuses me as english isn't my mother tounge.
It says "timing settings at start" whatever that means.

25 degres BTDC is WOT, I know that at least......
 

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