tohatsu 50 tldi mystery

[tohatsutldi]

hi guys .

i have a new tohatsu tldi with about 20 hours on it. it has run perfectly untill the last 2 times i took it out. when i am driving at wot about 3 minutes into the run the engine cut for a split second and if i keep driving at wot it will keep cutting . it seems like im lossing current to the engine for a split second at a time. i dont know if it is an electrical problem or a fuel pr0oblem. i noticed that the engine cuts out for a split second mostly on impact in the choppy seas. so that got me thinking that its a loose conection. i checked battry terminals and all wiring plugs and all seems fine.
so i tryed another run and the same thing happened .i noticed that the engine cut at about the same time into the run as it did the first run .so this got me thinking that it could be a fuel starvation problem. i cant understand what the impact on the waves has to do with it. anyway if anyone knows what is going on a would be most greatfull . oh is the ball pump on the fuel line suppose to be hard all the time. i noticed that the ball is soft sorted of like theres very low fuel flow in the fuel line. anyway im baffled to what is going on. could it be somthing to do with the throtel position sensor.

 

[TOHATSU GURU]

Re: tohatsu 50 tldi mystery

Take it into your dealer and have them determine the source of the problem and let them correct it.

 

[tohatsutldi]

Re: tohatsu 50 tldi mystery

hi guys .
well i did have the dealers maccanic have a good run on the boat . and the boat did the same thing again. it cut power at wot when going through choppy water. he said that it was not a fuel problem and it was not an electrical fault either. he said that it was the rev limiter that was kicking in when the stern of the boat lifted slightly from the water in the choppy weather. it makes sence to me .what doesnt make sence is why the engine is doing it now and didnt do it when i just got the engine., also the engine does not sound like it is over reving. is the rev limiter so sensitive that it kicks in even before the engine has a chance to over rev. should i take the maccanics word for what he said is the cause of this cut of power or should i investigate this further.
it sames strange to me that the over rev limiter would kick in without the sound of the engine over reving. i would like to take the dealer word but i am very sceptical . if it is the rev limiter i take my hat of to tohatsu for making a rev limiter on there engines with such a hi sensitvity.
anyone have a tldi that has experienced the same thing.

 

[TOHATSU GURU]

Re: tohatsu 50 tldi mystery

If the rev limiter is cutting in under these circumstances then you do have an electrical issue. It's more likely that you have an electrical short that is occuring at high speed while the boat is bouncing or that you have a defective CD module. The rev limiter is part of the CD module and should not activate unless you exceed 6000 RPM.

 

[tohatsutldi]

Re: tohatsu 50 tldi mystery

thanks alvin thats what i thought. now i have the task of convincing the dealer that it is an electrical fault. this maybe be a problem because im pretty sure that her is going to beat around the bush and say that the engine is running the way it is suppose to. if he gives me a hard time ill just have to report him to tohatsu. hopefully it wont come to that. thanks for your help alvin i apriciate it alot. alvin ar you a tohatsu technicion buy any chance.

 

[tohatsutldi]

Re: tohatsu 50 tldi mystery

well after alvins responce to my thread. i couldent get the fact that it can be an electrical short that is causing my engine to go nuts on the bumpy seas out of my head so i went down to the garage and did another therow check of all the wiring and plugs and i checked the battery terminals..
all was well with the harness but i did notice that the + positive wire to the battery was not conected to the terminal very well . in fact when i pulled on it just a little bit the wire came loose from the positive terminal. mind you it was not disconected but it was a very bad connection. tomm orow i will get some good heavy duty conectors and see how it goes hopefull the problem will be solved. if this turns out to be the fault. it is the fault of the technision from the deals that installed the motor. stupid moron. if this is the case ill be sure to let the dealer know.

 

[TOHATSU GURU]

Re: tohatsu 50 tldi mystery

I used to work for the Tohatsu distributor in the early 90's. Before and after I have been a dealer for them. And yes, I have been to Tohatsu service school.

 

[tohatsutldi]

Re: tohatsu 50 tldi mystery

thanks for your help alvin ill let you know if the terminal does turn out to be the culprit. im off to the garage this morning its still 6 am but ill go down change the terminals and hopefull go try thr motor. ill probably do a good couple hours spearfishing if all is well if not i will be to worryed about the motor to consentrate on spearfishing so ill go and tell the dealer . thanks cu

 

[tohatsutldi]

Re: tohatsu 50 tldi mystery

it wasnt the f****in terminal. i dont know what to do next. ill have to go talk yo yhe dealer again. if it was over rev or electrical problem wouldent the alarm and red light go on? ! cause it isnt. could it be that the prop is grabing more water sometimes in the coppy water and that is the reason for the split second drop in revs. the boat is reving up to 5300 when it is not interupted .when it is it will instantainyously drop to 5000 for a split second and regain the 300 revs. maybe it is the prop grabing more water and this is what causeus the 100 to 300 rev drop split seconds at a time.
like i said no buzzers sound and no visual alarms either.

 

[TOHATSU GURU]

Re: tohatsu 50 tldi mystery

Contact Tohatsu at 972-323-6003 and see what they think.

 

[tohatsutldi]

Re: tohatsu 50 tldi mystery

thanks alvin ill do that

 

[lots of boats]

Re: tohatsu 50 tldi mystery

Hi tohatsu guru, dealer.

Some of the TLDI's have the annoying quirk of loosing their throttle position sensor setting when they get bounced around more than they like. Unfortunatly, this has two effects, the one that is easily fixed is when the engine refuses to turn at more than 3000RPM indicating that one of the many things that bothers the throttle position sensor (TPS) has occured, and the throttle position sensor must be reset. That is easy, follow the book, takes a minute. The other thing that happens is the TPS just starts to cut engine
RPM anytime, for no apparent reason. The cure is to throw it away, or if you don't mind an unreliable motor, you just shut it down, wait a while try it again to see if the lights are behaving and ignore the problem. Having TLDI engines stutter happens to all the Tohatsu motors I have often.

 

[TOHATSU GURU]

Re: tohatsu 50 tldi mystery

The TPS sensor can loose it's memory if subjected to voltage fluctuations caused by loose wiring or if the sensor is defective. Every time you go over a wave and change the resistance on the propeller you can get a change in RPM. That's true for all propeller watercraft and it may be the case here. But your servicing dealer needs to check the engine out to eliminate something being defective.

 

[lots of boats]

Re: tohatsu 50 tldi mystery

TPI

The throttle position sensor losses its memory at times while not being subjected to any voltage or rpm fluctuations. I agree, voltage fluctuations are the most common problem, usually because battery terminals are not maintained properly. Also there are some types of batteries with hard lead alloy terminals that oxidize and turn black, and these should be avoided. You need clean soft lead terminals, tight stainless steel battery terminal fastners, some silicone spray on top, battery terminal caps and a battery box. These motors are really fussy about the battery condition. However, if the motor slams a floating log, a big wave etc, or the boat is in really rough water where you need the power to keep from taking water, then the TPS will often reduce RPM, and you are in trouble. Usually a shut down, restart will allow the TPS to forget how unhappy it is. However, at times, while just motoring along on nice flat water the lights will all flash, rpm falls, and the TPS needs to have a little break. We have one boat with an old 90TLDI with high hours that we grind up on plane with heavy loads probably 200 times a day. The TPS screws up ten to twenty times a day. The upshot is that even in a 90TLDI that isn't in the process of melting down you are taking a chance on random ignition problems, and if you are going to take these motors off shore, or in rivers where you can end up in a log jam, take a radio, take a friend in another boat, and have a spare kicker on the side. Also take spare plugs, the dealers love these plugs because the cost about $60 or more to replace a set, verses about $6 to replace a set of ordinary plugs, and if the plugs foul, wear out or fail, the TPS can have a tantrum, and so part of the crate of repair parts and stuff you need to run these motors you should be to carry the service manual that details the proceedure for resetting the TPS using the key and stop switch. Cheers.

 

[TOHATSU GURU]

Re: tohatsu 50 tldi mystery

Cheesey malice

 

[tohatsutldi]

Re: tohatsu 50 tldi mystery

im so sorry i didnt get the mariner 50 efi 4 stroke or suzuki or yammi
how was i to know that these engine where such a pain in the as . oh well no sence craying over spilt milk. the dealer hasnt solved my problem yet but ill be sure to tell him about the throtel sensor. does anyone want to buy a one month old tohatsu tldi

 

[tohatsutldi]

Re: tohatsu 50 tldi mystery

i just remembered that i once noticed that the throttel position sensor was a bit loose it moved a bit up and down . whould this movement be the problem in the engine cutting out. it seemed strange that something like that was so loosely conected and it sort of came to my attension that something about this sensor didnt seem right.should it be very tightly in place with no movement on its mount . if yes this is most likely the problem the sensor is moving up and down while the boat is bouncing on the waves i will tell the dealer on monday
what do you guys think. thanks for your help both of you . what di you mean by throw the tps away can the tps be aliminated or did you mean thow it away and get a new one

 

[tohatsutldi]

Re: tohatsu 50 tldi mystery

what does the tps do exactly be paceint im trying to learn something here.

 

[TOHATSU GURU]

Re: tohatsu 50 tldi mystery

"im so sorry i didnt get the mariner 50 efi 4 stroke or suzuki or yammi"

So am I.

 

[tohatsutldi]

Re: tohatsu 50 tldi mystery

not as much as i am