Need Tohatsu help

[daveracerdsh]

Tohatsu

thank you Darren...good advice and that is very generous of you. It is possible that I was getting an false reading off of gps....anything is possible. As weekend went by at Yelm you could "feel" rig getting more and more sluggish...I will try all of the ideas you mentioned though. Dave

[PRO-MOTIONRACING]

Just an Idea, if I remember correct the cylinder liners in those don't have a lot of aluminum around them, perhaps it could be some sort of distortion caused by hot and cold spots as the water was a little cold. This could cause an out of round situation and increased drag as it ran. This would also explain why when that other guy honed his out to the loose side it ran better.

[daveracerdsh]

Tohatsu

Interesting...I wonder if I am doing a wrong warm up procedure..I have cylinder head temp gauge..sensor is on plug number one. I back rig into water, light it off, and let it idle (around 1000 rpm) till it gets to about 150 degrees. This is usually done during the heat before I run. When 3 or 4 minute gun goes off I get the thing on plane as gently as possible, letting the temperature build up to around 180 before I start getting on the thing. During race conditions, the motor seems to run in the 210-225 range...depending on ambient water temp. (I actually keep track of stuff like that) When we tested last week, the motor never had a chance to cool down. I would come in, tweak a few things, then right back out. I wonder. like I mentioned earlier...if there is something like Dale Bartley mentioned, where the block takes a "set" due to warm-cold cycling. Just a thought. Dave

[form-e one]

did you rebuild it with wiseco pistons??,, if soo clearences need to be different..

[daveracerdsh]

Tohatsu

Nope....this is the 2nd full season on ,020 bore. Used Tohatsu pistons.

[pstock800]

How did you break in the motor, mine ran in my front yard on a hose for about 4hrs. then another 2 hrs of laps on the lake. using mercury 2 stroke oil. then switched to amsoil blue for racing. havent had a problem sence. i run mine at 50to1 mix. plugs are cardboard brown. enven on a hot day i dont think it runs over 190.

[G Stillwill]

Try taking a compression test when the motor is hot that should tell if the bores go out when its hot. What oil did you break it in with anything but pure TC-3 outboard oil will glaze the rings and they will never seat.

[jeff55v]

Nope....this is the 2nd full season on ,020 bore. Used Tohatsu pistons.

USED pistons?
Aren't new ones available? Have you checked your skirt clearance? You might be getting excessive slap. That's something that wouldn't show up on a compression test.

[daveracerdsh]

Tohatsu

I mean I USED Tohatsu pistons....broke motor in with pure non-synthetic oil...20-1 ratio. Everything on the block checked out perfectly before assembly...correct piston to wall clearence etc. Mr Stillwell brought up a good point..if never occurred to me to check compression both hot and cold....if here is a heat related issue that could manifest itself when checked hot. Thank you for the tip. Is ironic...I have been involved with racing for over 25 years...and it is so cool that I learn something new at every race or in some conversations. Pretty neat...dave

[form-e one]

mmm brake in,,, yamato merc 44 and v-rude,,,, 1 dry fire get it warm,,,, then race full tilt 25 years now...

[form-e one]

yaa but dave you where telling me you have reverberation coming back threw the carbs when ya run it??? even with new reeds???..

[daveracerdsh]

Reeds

There seemed to be more fuel in belly pan then I expected.....it could be that I got a bad set of reeds from the factory. If so, I have another set I can use this weekend.

[mercguy]

mmm brake in,,, yamato merc 44 and v-rude,,,, 1 dry fire get it warm,,,, then race full tilt 25 years now...

that explains why you spend alot of time behind a tow rope...........

signed........"one of those Reg10 guys that can read (and spell)"....

[form-e one]

looks like ya read something ,,hehe

[Kevin McAfee]

Not to change the subject, but here is some good reading on one guys break in theory.
http://www.mototuneusa.com/break_in_secrets.htm