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Tohatsu 140A2 - a few questions

5

5teve

New member
HI All... new user to the forums and one of the very few tohatsu 140 owners in Western Australia.. and i have some questions i hope you can help me with...apologies for what i am sure will be a very disjointed post..

Ok we have owned the 2003 motor for the last 4 years and in that time it has been great. Well great until we took it for servicing. Then it was great for a few runs and started to have a few issues. Subsequent servicing hasnt helped and as the 'issues' are a little hit and miss they have been hard for anyone to pinpoint. the motor has approximately 350 hours on it.

The main issue is that every time it goes for servicing we are told 'its running a little lean' so they richen it up, needless to say fuel economy has been going down the pan for some time.

We have had some issues where 2500rpm is the max rpm we can get on WOT with no alarms and it has had very little power. I usually change the plugs and give it a treatment of Subaru upper negine cleaner to decoke it. The engine gets some high speed runs and also low speed runs all in all fairly varied (due to the somewhat interesting seas we get over here). This treatment normally brings it good again.

Another issue is that it has started to be very smokey on startup, never used to be and also seems to be using too much oil. hard to say how much as i use the auto mix and from what i hear they are reasonably good.

OK now i'm not looking for any info on the above unless you have any :) however i am slowly learning about the motor and how to adjust various things (i dont want to rely on the dealers) I have got myself the seloc manual and am looking to find a factory service manual too.

I have found that by moving the timing link towards TDC while its idling seems to make the idle very much smoother. After looking in the manual it appears that 10Deg ATDC is the idle setting and 19-21deg BTDC is the WOT setting. The confusing part of this is that it also says that the block split line is equal to TDC and the centre of the adjuster ball is the mark, but mine has marks on the stator plate and they dont seem to agree with this. Hopefully from the pictures below you can see that the stopper is allowing the rotating plate arrow to be bang on 10ATDC and this gives rough idle. if i set the link arm to spec (127mm i think) then it brings it to about 5deg ATDC and well off the stop. It also allows me to knock the idle screw back by about 4 turns to maintain 900rpm (out of water) its as though the fixed plate (with the timing marks) is out by some degrees. It also isnt anything like how it is shown in the manual. when adjusted to 'run nice' the stop seen on the LHS of the pictures cannot be adjusted out far enough to contact the rose joint.

so my question is... has anyone got any info as to what is right? I dont have much confidence in any of the dealers here.

IMG_0090_small2.jpgIMG_0089_small1.jpgIMG_0091_small3.jpgIMG_0092_small4.jpgIMG_0093_small5.jpg

The other thing i need to know is there a reasonably straighforward way to check the oil flow or adjust it? i'm convinced it is over oiling which is leading to the smoke on startup (if left for 10-15 minutes from shutting down)

Am i also correct in assuming the dealer was talking out of his butt when they said it was running lean? as far as i can determine the flow rate / mixture of fuel can only be adjusted for idle and the actual running mixture is preset and un-adjustable? hints and tips on this would be greatly appreciated!

Final thing is balancing the carbies... is there any way of doing this? i have seen reference to using vacuum gauges and water tubes etc, but the carbies dont seem to have any vacuum test points... any hints on this also?

Thanks very much in advance for your help...

Steve
 
Lenard said:
I recommend you to contact your Tohatsu dealer and/or buying a factory original service manual.
Click to expand...

Thanks... As i stated i am looking for a factory service manual and will probably have to source one from the US as we cant buy them easily over here. i have some pricing already so will have that ordered.

As for the dealers... They are expensive and in my opinion not good (we only have 3 in the whole of Perth and most of those arent renowned for being good) it cost me $550aud (about $600us) for them not to resolve the power issue when in the end it cost a new set of plugs (which they didnt replace) and a can of upper engine cleaner.

A service is around the $600AUD mark and as i said each time i get it back it runs OK for a trip or 2 then needs work again.. doing it myself and understanding it myself should eliminate this..

Thanks

Steve
 
Sounds like you need a full *and proper) tune-up, including verifying oil rate, carb settings and also link-and-sync.

I'll have to confirm timing link settings once I am at the office later this morning, but it seems you have conflicting timing data. Yes, mixture under power is controlled by fixed jetting, but idle mixture can be adjusted via the pilot screws on each carb.

Yes, the oil pump can be measured/adjusted. the info is in the Factory service manual. I would skip the aftermarket manuals, as they tend to be too general.

Yes, you can sync carbs with any good multi-carb synchronizing manometer. One good one is http://www.motionpro.com/images/documents/syncpro_tech.pdf
 
Thanks for that Paul

I am trying to find a service manual and am waiting on some parts pricing also (as i may as well get more than one item delivered from the states!) so i should have that done soon..

I would agree that i need a full and proper tune up.. but i have no confidence in anyone unfortunately! I am likely just to keep it running until summer passes and then i'll start stripping and cleaning and adjusting using the manual. The great thing about the motor is that even tho it has had and is having a few issues it always starts and always runs..

I have sneaked a look at a downloaded manual (dont ask) but there is no mention of oil measurement. Do you have the correct part number for the manual for the 140A2 2003, or even better do you supply them overseas?

Regarding the 4 way manometer, how do you use them on the tohatsu as it has no connection points? is it just a case of rigging something up? or are adaptors available? I was looking at a unisyn (single manometer but probably more hassle) as it just rests over the air inlet.

Thanks again for the info... and let me know if you can supply the manuals..

Steve
 
The Tohatsu 3 and 4 cylinder 2-stroke service manual is Part # 003-21036-1, $45.00US. Yes, we can ship anywhere; but freight and customs costs will add significantly to the pricing to your door.

The ignition timing link spec is 5" (127mm). The throttle link spec is 6.22" (158mm). Stopper C should be 0.551" (14mm), and stopper D should be 0.708" (18mm) to set the WOT timing limit; Stopper E is for idle timing... Idle timing should be 10 ATDC, WOT timing should be 20 BTDC, +/- 1 degree for everything. Use the pointer and the scale on the magneto breaker plate. You must set timing before synchronizing carbs.

The Factory way of syncing carbs is to zero-out the throttle stops (then set the carb to 5 degrees open throttle plate), then adjust pilot mixture screws, then finally adjust the idle stop screw (in the water with the boat free to move) to 900 in neutral, 700 in gear, THEN adjust the oil pump aperture. The Factory method does not utilize a manometer, but a uni-syn synchronizer is OK, as it fits on the carb throat. I have used them on Corvair motors for years.

FWIW, the RPM limiter will engage at about 2800 +/- 400, if either the oil tank is low or water pressure is low. Otherwise, the ESG engages at about 6,000 RPM.
 
Hi Paul

Thank you so much for taking the time to relay that information to me. Its very much appreciated. I have located a manual now and have to wait for it to be shipped. Shipping fortunately wasnt that much and i have combined it with some spares (as nobody seems to want to sell them to me over here) and customs in Aus are generous with a $1000aud limit before fees are incurred (FYI if your interested!)

I will check linkages before we do a long run on Saturday just to confirm all is ok.

I will try and find a unisyn or similar online as i'm sure that will help, as will a timing light so i can see if anything is amiss.

I have encountered the limiter several times so am aware of its operation, as we have a lot of loose weed in the seas here which reduces water pressure. Thanks for repeating the info however.

I'm hoping the factory manual will have all the info i need, as the one i looked at skims over the 140 quickly. My main concern at the moment is the oil metering.. and that is the main thing i want to address.

Again thanks for your time and help... much appreciated when i am pretty much on my own..

Steve
 
Happy to help. Our small dealership survives because of service. We try to do what we can for the DIY customers... about half of our local customers fall in that category. If you need anything shipped, let me know, we're happy to ship worldwide. I have parts customers in Uzbekistan and Peru, as well as the US and Europe. Long distances for a dealer in the US... we have them because we provide service and advice when they are having trouble locally :)
 
tohatsu_guru said:
The carbs are dirty. Just clean them correctly and all will be well.
Click to expand...

The carbs were stripped down and re-assembled about a year ago, although as per everything i'm not 100% it was done correctly by the dealer (at a cost of $550 with no parts replaced and no improvement). I have been considering getting the repair kit for the carbs and going through them cleaning and adjusting. Is a single repair kit for the full 4 carbs or do i need 4 repair kits? The part number i have is 3C7871220 although that looks like it may have been superceded to 3C7871221.

Are the reeds something i need to look at also? at 350 hours and 9 years old could they be a little tired? if so is it worth looking at the boyosen ones or just the standard.

Out of interest i ran the power tune treatment yesterday and had lots of black gunk / slime come out, this is 6 months after doing a decoke with subaru upper engine cleaner. Even after treatment the centres of the piston tops are still fairly heavily crusted with carbon but clean towards the outer edge , so after this weekends potential long run (hoping the weather holds) i will stuff another power tune treatment through it and see if i can shake the last lot. At least if the pistons are clean and happy i can work back to everything else once the summer has passed (wind and seas vary quickly here in the summer and a forecast can suddently come good so we HAVE to go out then!)

Thanks for your help once again

Steve
 
Part# 3C7871221M, $193.07, does all 4 carbs. You need to do a complete disassembly, a 4-hour bath in carb dip, spray-out with generic carb spray, then a careful reassembly/adjustment. Stay with Stock reeds. They spit less, and give better all-around performance. No need to replace them unless you observe that they are tired.
 
Thanks Paul for confirming that.. a job for the months of April onwards.. gives me until august then when the whales come past!

The manual has the specs for the reeds so i will go though that. I'm determined now that the dealers who do half a job arent going to get my money any more!

Thanks again guys.. and Paul.. i'll be in touch regarding parts when i'm ready (and allowed!)

Steve
 
Sorry guys can i confirm terminology here..

When doing a link and sync and oil pump aperture check (ie checking the scribe lines) the manual states to 'set the throttle to fully closed'

Can i just check that it means back the idle screw right off until the throttle butterflies are shut rather than ensuring the motor is on its lowest idle setting (5 deg or whatever it is). This would then mean that all settings (ie timing, pump marks etc etc) would be out from their specification once the motor is set up to idle at 900rpm? This probably is a simple thing to ask... but i can see it would make a big difference!

One other thing is that to check the oil pump marks it says to line them up with the throttle fully closed, apart from the fact that the pump is barely visible, i cannot get the lines to match. The diagram shows them to be parallel and co-linear, however mine will not do this. I can get them parallel but then they arent close to being in line or i can get them close together but not parallel (if that makes sense? if not have a look at my dodgy diagram below... ) any advice on this?

oil aperture.jpg

Thanks again guys

Steve
 
Make the setting at idle, (throttle handle closed down all the way), not with the plates completely closed. Otherwise, you will be sending too much oil to the mix, especially at slow speeds. Don't worry that the scribe marks aren't parallel... just line then up touching.
 
Hi Guys

An update for you, I redid all the link and sync on Thursday night and went down to the marina to test that all worked ok, which it seemed to be. I didnt balance the carbs as i dont have the manometer yet.. but it seemed to idle smoother than it has in a long long while. Hard to tell with the smoke as it was dark and smoke always seems worse when viewed by bright torchlight.

Saturday was the Key day as we had a trip to an Island called Rottnest Island. Its 38km each way and the forecast was reasonable for Western Australia. Engine started with a puff of smoke Saturday morning but it cleared very quickly, and i suspect it was still power tune / carbon coming out. It ran faultlessly for the hour it took us to get there. 4 of us on board 110l of fuel and enough gear (as 2 were camping) to sink most boats.

This morning after sitting over night, engine started first flick, tinyest puff of smoke and then ran faultlesly back for an hour. Seems responsive smooth and quieter. No 2 stroke smell either which is back to how it used to be. We maintained about 19knots each way so as to keep it smoothish for the MIL. Fuel usage for the trip was about 55litres, so no more than usual. I just have to change impeller and then come winter (relative term as we use the boat all year round) i will recon the carbs. Hopefully my manual will arrive shortly too.

Ok i now have a question for you...

If the pistons ect were heavily carbonised, would the carbon deposit be able to hold oil / fuel? My reason for asking is that i was pondering on the possibility of this happening and the fuel evaporating leaving just oil.. and causing smokey startup?

Thanks again for your help.. i'll let you knowhow i go with the other jobs!

Steve
 
If the chambers and piston tops are coked up, yes, you can get a fair amount of smoke as you burn that off.
 
Hi Paul

Thanks again for your input.. just to clarify what i meant was prior to decarbonising is the fuel mix able to soak into the carbon if there is enough, causing smoking on startup due to the oil soaked into the carbon (and the petrol having evaporated) therefore altering the fuel oil mix on startup until the oil has combusted.

if thats what your reply was saying then great thanks... it explains why there is less smoke now!

Steve
 
5teve said:
HI All... new user to the forums and one of the very few tohatsu 140 owners in Western Australia.. and i have some questions i hope you can help me with...apologies for what i am sure will be a very disjointed post..

Ok we have owned the 2003 motor for the last 4 years and in that time it has been great. Well great until we took it for servicing. Then it was great for a few runs and started to have a few issues. Subsequent servicing hasnt helped and as the 'issues' are a little hit and miss they have been hard for anyone to pinpoint. the motor has approximately 350 hours on it.

The main issue is that every time it goes for servicing we are told 'its running a little lean' so they richen it up, needless to say fuel economy has been going down the pan for some time.

We have had some issues where 2500rpm is the max rpm we can get on WOT with no alarms and it has had very little power. I usually change the plugs and give it a treatment of Subaru upper negine cleaner to decoke it. The engine gets some high speed runs and also low speed runs all in all fairly varied (due to the somewhat interesting seas we get over here). This treatment normally brings it good again.

Another issue is that it has started to be very smokey on startup, never used to be and also seems to be using too much oil. hard to say how much as i use the auto mix and from what i hear they are reasonably good.

OK now i'm not looking for any info on the above unless you have any :) however i am slowly learning about the motor and how to adjust various things (i dont want to rely on the dealers) I have got myself the seloc manual and am looking to find a factory service manual too.

I have found that by moving the timing link towards TDC while its idling seems to make the idle very much smoother. After looking in the manual it appears that 10Deg ATDC is the idle setting and 19-21deg BTDC is the WOT setting. The confusing part of this is that it also says that the block split line is equal to TDC and the centre of the adjuster ball is the mark, but mine has marks on the stator plate and they dont seem to agree with this. Hopefully from the pictures below you can see that the stopper is allowing the rotating plate arrow to be bang on 10ATDC and this gives rough idle. if i set the link arm to spec (127mm i think) then it brings it to about 5deg ATDC and well off the stop. It also allows me to knock the idle screw back by about 4 turns to maintain 900rpm (out of water) its as though the fixed plate (with the timing marks) is out by some degrees. It also isnt anything like how it is shown in the manual. when adjusted to 'run nice' the stop seen on the LHS of the pictures cannot be adjusted out far enough to contact the rose joint.

so my question is... has anyone got any info as to what is right? I dont have much confidence in any of the dealers here.

View attachment 3724View attachment 3725View attachment 3723View attachment 3726View attachment 3727

The other thing i need to know is there a reasonably straighforward way to check the oil flow or adjust it? i'm convinced it is over oiling which is leading to the smoke on startup (if left for 10-15 minutes from shutting down)

Am i also correct in assuming the dealer was talking out of his butt when they said it was running lean? as far as i can determine the flow rate / mixture of fuel can only be adjusted for idle and the actual running mixture is preset and un-adjustable? hints and tips on this would be greatly appreciated!

Final thing is balancing the carbies... is there any way of doing this? i have seen reference to using vacuum gauges and water tubes etc, but the carbies dont seem to have any vacuum test points... any hints on this also?

Thanks very much in advance for your help...

Steve
Click to expand...
hello can any one pls tell me how many degrees is every mark on those pics ???? the arrow means 0 degrees ?
 
You need to understand that a 2 stroke will smoke on start-up and it is quite normal.----When engine is stopped oil runs down all the parts and collects at the bottom.----On start-up this oil is immediately put back into use and some unfortunately is burned and is seen as smoke.---------Monitor oil usage per the amount of fuel that is being used.-----You should not adjust the automatic oiling based on smoke that you see on start-up.
 
costa costa said:
hello can any one pls tell me how many degrees is every mark on those pics ???? the arrow means 0 degrees ?
Click to expand...

As I noted in post 6 above:
The ignition timing link spec is 5" (127mm). The throttle link spec is 6.22" (158mm). Stopper C should be 0.551" (14mm), and stopper D should be 0.708" (18mm) to set the WOT timing limit; Stopper E is for idle timing... Idle timing should be 10 ATDC, WOT timing should be 20 BTDC, +/- 1 degree for everything. Use the pointer and the scale on the magneto breaker plate. You must set timing before synchronizing carbs.
 
thank you ....i know the settings . the thing that i was asking was the degrees on the plate . i found that every small line is 2 degrees and the biger lines are 5 degrees the arrow is tdc .
 
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