I think the Auto choke on my 2001 Tohatsu must be out of adjustment

[boatster]

I noticed the electronically heated auto choke on my 2001 15 tohatsu 4 stroke has an adjustment for how much the choke needle sticks out. Does anyone know where the factory adjustment should be? Or where it should be? The motor is really hard to start and I'm starting to think its because the choke is out of alignment. It might be flooding the motor or.... starving it I'm not sure. I cleaned the carb multiple times so I think its related to the choke circuit. Once the motor is started it runs no problem. I can stop it then immediately restart it again. But if I let it sit it will be hard to start after awhile again.

 

[TOHATSU GURU]

Re: I think the Auto choke on my 2001 Tohatsu must be out of adjustment

I didn't know it was adjustable...But, I'll check into it for you.

 

[TOHATSU GURU]

Re: I think the Auto choke on my 2001 Tohatsu must be out of adjustment

There is no adjustment on the auto choke. It either moves when current hits it or it doesn't.

 

[boatster]

Re: I think the Auto choke on my 2001 Tohatsu must be out of adjustment

Thanks Elvin,

Mine it seems was partially taken apart. It was unscrewed some which changes the way the choke needle closes off when its warmed up. The motor is still hard to start. I screwed it all the way down on itself and it seems to have increased the ease of starting but I have to literally crank away like 6-7 times before the motor starts coming to life. I've kinda thrown out my shoulder as a result of this. I know this isn't right.

The carburetor is as clean as I can get it and the only thing I can guess thats left is either valve adjustments, or the seal on the carb bowl needs to be replaced. Its as if there is some small vacuum leak that needs to be overcome by multiple continuous cranks on the cord.

What should I do next?

 

[TOHATSU GURU]

Re: I think the Auto choke on my 2001 Tohatsu must be out of adjustment

I hate to see you throwing parts at it but, I would replace the choke unit. If someone screwed around with it before, then you have a good chance they have damaged it. I've never seen a bad one myself, although we have sold a couple over the last 8 years.

 

[boatster]

Re: I think the Auto choke on my 2001 Tohatsu must be out of adjustment

I suppose thats not a cheap part. Is there a way I can test if it is operating properly? When I took it apart it seems its supposed to open and close like a thermostat with a little heater on the end of it. Can I test whether or not that little wax housing piece is working or not? I know the heater is working because it is gettting warm.

The thing is, the motor is hard to start when its straight cold so the motor is already choked. Is that correct? The heater on auto choke eventually unchokes the carb as it warms up. I'm totally guessing here. I'm wondering if I need a new float bowl seal because the one I've got is somewhat flattened out.

Thanks for your help Elvin.

Adam

 

[TOHATSU GURU]

Re: I think the Auto choke on my 2001 Tohatsu must be out of adjustment

You can remove the choke from the carb and hit it with 12 volts. You should see the needle move after a few seconds. The problem is that if the needle isn't returning to its correct position when cold you aren't getting choked...At least not enough. It is possible the bowl o-ring could be leaking, but I wouldn't bet on it.

 

[boatster]

Re: I think the Auto choke on my 2001 Tohatsu must be out of adjustment

Thanks Elvin,

I'll give it a shot. Can I just hook it up to a normal car battery? Or will that fry it out? How much voltage and amps is it supposed to get when the engine is at idle?

I also measured the resistance on the choke to be 17 ohms.

Otherwise I'll order the parts from your site internetoutboards.com . Thanks for your help

 

[TOHATSU GURU]

Re: I think the Auto choke on my 2001 Tohatsu must be out of adjustment

The car battery is fine. There are no specs on the part available.

 

[boatster]

Re: I think the Auto choke on my 2001 Tohatsu must be out of adjustment

Well I took the motor out today and actually ran it for the first time. Somehow after running it full throttle and really giving it the Italian Tuneup it now starts easily. Must have freed a really stubborn particle. However now I have surging at full throttle and the check engine light goes on. Sometimes the motor simply shuts off. I think the engine is overheating. I didn't check and replace the thermostat but I suspect this could be the culprit as my older Tohatsu 8hp 2 stroke had the same issue. Today was the first time this motor has been really used in probably 2-3 years so I imagine the T-stat must have gone bad from disuse seizing or something. I'm going to check it out tomorrow.

I hope this resolves the issues with this motor. Thanks again Elvin.

 

[Bob Le]

Hi.
I also have been having trouble with my 25HP Tohatsu 4 stroke MFS25A.
A lot of miss firing on one cylinder only. After a lot of testing, experimenting etc, finally got to identify the bottom cylinder as being the one misbehaving.
Turned out to be the plug - it looked fine, but when replaced the problem went away.
However, I now have a number of adjustments to re-do, Throttle balance I can do by listening to the "suck" volume on each carb, slow running mixture by tuning to best tickover, but the auto choke (part BPQFU) - not sure where it should be on its fine thread adjustment. I will check it's function on a 12V power supply, & measure the movement (do we know how much it should move ?) but I dont know whether to screw it all the way into the threaded collar, or is there a set number ot turns out ? any advise welcome. Also, is there a better way of tuning the slow running mixture other than by going for smoothest idle?

Bob.

 

[pvanv]

Bob,

1. This post is several years old; you should start a new one.
2. The original post was about a different model motor with a different symptom.
3. The carb sync should be OK as long as you didn't adjust (file down) the throttle stops of the individual carbs; The master idle stop (on carb 3) adjusts the entire linkage.
4. The pilot screws of the individual carbs are preset by instrument at the factory, and should not be re-adjusted; The EPA requires plugs to block access to the pilot screws. If you have removed the plugs and adjusted the pilot screws, start by setting them back to the original settings.
5. The auto-by-starter solenoid is not adjustable.

If you have disturbed any/all of these settings, use a carb synchronizer, such as a Uni-Syn or SyncPro to get them back where they belong.

 

[Bob Le]

Thanks Paul.

1. Noted
2. Noted
3. the upper two carbs have their own idle stop screws, which I have set up previously - no filing required. The bottom screw adjusts all 3
4. Plugs removed years ago, & have re-tuned several times - all approx 2 turns out. Just wondered what the official way was to set them.
5. The ADS unit on my engine has a fine male thread in the upper (active) part which screws into the lower part which contains a spring. I don't believe the two were originaly screwed tightly together - rather that the top part was "unwound" approx 2¼ turns. This is why I think that this is an adjustment of how long the choke is active for - ie the further out the top part is then the longer it will take for the needle, & outer cylinder to drop down, & seal off the starting jet.

I am in the UK by the way.
Regards
Bob.

 

[pvanv]

Bob,

Pilot mixture can bet set in the usual way... with a good, experienced ear, and a very accurate shop tach. Starting at 2 turns is good.

In the US, we don't have idle stop screws on the #2 and #3 carbs, so I would set them like any other multi-carb setup The SyncPro manometer is a good tool for that, or again, the experienced ear.

I havent seen an ABS solenoid disassembled, as they are only available as a unit. I would likely start with it screwed all the way together. Testing with 12v is a good idea. It should fully expand in a couple of minutes.