tohatsu 40 needs tlc

[louis165]

i have a 1993 40hp tohatsu it will surg at wide open. its on a 15 ft express at 30 mph with about 400lbs inside prop is a 14p:

 

[ziemann]

Re: tohatsu 40 needs tlc

We need more information. Start with the basics. Look at fuel and spark... There are alot of thing that can cause that, but start with the obvious.

Check the simple things such as spark plugs, old fuel, etc.. Check or replace all fuel filters that can cause fuel restrictions at high RPM. Most of the time at high speed it is something simple that you may have over looked...

What RPM is this occuring at? Is the primer bulb hard or sift when this occurs?

You get the idea....

 

[louis165]

Re: tohatsu 40 needs tlc

the plugs look good filter is good i pumped the bulp butt not hard i dont know the rpm its a tiller no tach it doesnt sound like its rpm's are very high never had a 3 cylinder so not sure . the prop is a 14p not a 15p I just got the motor so any specs would help and preformance mods would help I want to bring it back to life

 

[louis165]

Re: tohatsu 40 needs tlc

the plugs look good filter is good i pumped the bulp butt not hard i dont know the rpm its a tiller no tach it doesnt sound like its rpm's are very high never had a 3 cylinder so not sure . the prop is a 14p not a 15p I just got the motor so any specs would help and preformance mods would help I want to bring it back to life

 

[pvanv]

Re: tohatsu 40 needs tlc

A motor of that model year (1993) would be a 50-to-1 premix, carbureted, 2-cylinder, not a 3-cylinder. A newer 40 would be a TLDI: Injected 3-cylinder. Completely different animal.

See if you can get the actual model from the sticker so we can help you more.

 

[louis165]

Re: tohatsu 40 needs tlc

M40D 3c8 33225 this is the numbers on the tag its a three cyl. three carb. motor is gray with no oil inj hope that helps!!!!

 

[TOHATSU GURU]

Re: tohatsu 40 needs tlc

M40D....Your surging could be anything. Y O U will have to start testing the engine to determine what system is involved with the surging before you can start to determine what part has failed. I would urge you to pick up a service manual before you go any further.

 

[louis165]

Re: tohatsu 40 needs tlc

i dont know what year it is M40d 3c8 33225 is whats on the tag i was told it was a 1993. cant order manual with out year it is a 3 cyl 3 carb motor its gray in color spark is blue at 1/2 inch. comp. is 130 on all three cyl.

 

[TOHATSU GURU]

Re: tohatsu 40 needs tlc

Tohatsu does not use years to determine what manual you use. Also, the year is unimportant to determine what parts you need. The model number is all you need in both cases. Is your surging rhythmic or is there no pattern to it other than it occurs at high speed?

 

[louis165]

Re: tohatsu 40 needs tlc

its only at wot. i have carbs soaking. reeds look ok from outside. im thinking about a set of boysen reeds will they help on out boards. im an old dirt bike rider. im also trying to find a tohatsu dealer my area code is 71463 thanks!!!!!!!!

 

[TOHATSU GURU]

Re: tohatsu 40 needs tlc

Your two closest dealers are in Jennings and Alexandria...Neither one is that close .

On the surging. Does the surge sound seem even and spaced out where it kicks in and out almost like it is timed or is it ragged with no rhythm to it?

I'm not big on aftermarket reeds as they seem to make the idle rough...Although they do seem to give the engine a little more punch.

 

[louis165]

Re: tohatsu 40 needs tlc

it is consistant . but i think i found the problem it has water on #3 cyl . it has red permatex on the cover on the head im not sure what its called its not the termastat its the one the termastat bolts to. the head looks to have 2 gaskets on it . hope its a gasket or head not the block what do u think?

 

[TOHATSU GURU]

Re: tohatsu 40 needs tlc

I think that previous owner sold you an engine with a problem that they either couldn't fix or was too expensive to fix. You should probably stop and take it into a dealer to be evaluated.

 

[louis165]

Re: tohatsu 40 needs tlc

he must have tried to fix it the mech. i know would not have used red permatex any way he lied if it can be fixed ill fix it .i like bringing old back thanks 4 the help . about how much is a complete rebuild kit

 

[TOHATSU GURU]

Re: tohatsu 40 needs tlc

There is no rebuild kit as what you would replace would be determined by what is broken.

 

[louis165]

Re: tohatsu 40 needs tlc

i just pulled head off i cant visualy see any thing wrong with the cyl it did not have a thermastat mybe a bad spot on the gasket but not sure if that would make it leak it was wright next to the cyl. but the metal ring looked ok ill clean the head up & try to find some where to have it checked

 

[louis165]

Re: tohatsu 40 needs tlc

was not head or gaskets. im going to try exhaust plate today. what can i try next

 

[TOHATSU GURU]

Re: tohatsu 40 needs tlc

Tear the block apart or take it to a dealer.

 

[louis165]

Re: tohatsu 40 needs tlc

the base gasket under the power head was bad!!!!!!!!