1992 Yamaha 70 BETO L Wont Start

[Dorado]

Hello, I have owned the above Yammi 70hp OB for 16 years now and it has started first time, every time since new until about June this year when she started to act up. I had a major service performed on it in June and it ran sweetly after that when I used it for a week in July. I went to start it last week for a fishing trip and she would not start despite having brand new plugs and following the correct starting procedure, ie, squeeze fuel bulb to pump the juice til bulb is hard and then prime the motor with the lever and turn the ignition key for 5 secs before closing the primer lever and turning the ignition key again from which she usually fires up immediately. But not this time. She had fuel, new plugs but she wouldn't fire and I ran the battery flat trying to get her firing. A few days later I tried again following the exact same starting procedure and she burst into life on the first turn of the key whilst the primer was engaged. It's never done that before. It continued to start and ran normal for a hour or so. I tried to start her up again this morning but she would not fire at all. Checked the plugs and ignition coils, all unfouled and plenty of spark from each plug so the plugs/coils are fine. Next checked the fuel lines and filters and all fine there too. I am really stumped on why she wont fire up and on other days she bursts into life. Could it be a problem with the micro-processor? Any ideas, help really appreciated. Also, I could really do with an engine/service manual for this motor. The existing owner's manual doesn't help much and I would like to service it myself, as much as practicable.

Thanks,
Dorado

[Blackened]

G'day

My guess is electric, maybe the CDI pack or equivalent?

Wait for Noelm or Spaniard King to reply, these 2 are in the know with this kind of o/b

Dave

[Dorado]

Thank you for your reply and yes I am also thinking along the same line that the CDI pack or whatever has an intermittent fault. Either that and or the kill switch which is more exposed could be shorting somehow.

I have pulled aprt the remote control box and inspected the ignition and kill switches and there are no obvious signs of corrosion or shorting out but I suppose that the 2 units themselves could've shorted out inside? I wonder if there is a way to disable the kill switch because if it has failed and I can disable it then I can try to crank it up again and if it works then I'll just replace the kill switch unit. In the engine itself is a Micro-processor with a label on it for emergency starting indicating to bypass some wiring within and to refer to the Owner's manual. Only thing is the manual doesn't mention anything about it!! I am wondering though if by bypassing the correct wires whether this in fact is bypassing the kill switch??? I am not sure. It really does seem though as if the kill switch is self activating because whilst the engine cranks over it just doesn't fire at all...sigh*

Thanks,

[FNQCairns]

Kill switch might be a culprit as in other things electrical also but IMO your problem is all down to procedure, is it starting OK warm?

If so try and discount anything else but tuning, variability and starting procedure. Starting procedures can simply change, the trick is to find one that covers all of the variables on any one day, variables can include, the amount of time it spent at idle before being last shut off, the age of the fuel in the lines/carbs. the air temperature at which it is being started and how long it was since it was last started.

I have more or less the same design of engine and it took me months to refine one starting procedure that covered all these bases, so far...nearly flattend a battery once, have it pegged now, still I may need to review even the one I use now if the engine forces me too sometime.

A real big tip with standard 2 strokes is whenever a problem like this exists use LOTS of initial throttle and i dont mean rev it's ring out just initial throttle, getting harder to do with modern dumbed down linkage lockouts etc but it can very often get an engine started that wouldnt have any other way short of an ether spray.

cheers fnq

[Dorado]

FNQCairns, when it does start and I run it for any amt of time thereafter, then it continues to re-start each and everytime I turn the key, whilst the engine is still warm.

But, I am trying to start it cold atm and I am following the same start up procedure as I have done for the last 16 years but it will not fire. Usually, it fires immediately but recently I've noticed that it may kick or fire once or twice and it eventually catches and runs fine, albeit a little rough until I give it some revs.

at the moment it's stone cold and not firing at all which is very unusuall as this Yammi has always started or fired when cranking it over.

Thanks,

[FNQCairns]

FNQCairns, when it does start and I run it for any amt of time thereafter, then it continues to re-start each and everytime I turn the key, whilst the engine is still warm.

But, I am trying to start it cold atm and I am following the same start up procedure as I have done for the last 16 years but it will not fire. Usually, it fires immediately but recently I've noticed that it may kick or fire once or twice and it eventually catches and runs fine, albeit a little rough until I give it some revs.

at the moment it's stone cold and not firing at all which is very unusuall as this Yammi has always started or fired when cranking it over.

Thanks,

Yeah mate that's it different degrees of tune etc as above, need differing starting procedures, if someone bought your engine today they would probably find a new and fairly different but reliable way to start it given time and enough cold starts to get there (the hard part).

Try more throttle if you can combined at the same time the primer as it only works when the engine is drawing fuel. If I try and start my 90 of the same design as yours just bigger the same way you do, half of my trips wouldn't have materialised from the ramp, yet the bloke next to me with the same engine as mine could use your stating procedure and have no problems...hope you get what I am saying here, how you started it in the past no longer matters as it has been played with inbetween times amongst other things.

The fact that it starts well warm points away initially from any other problem outside of what I posted above.

cheers fnq

[Dorado]

Yes I do understand what you are saying, thank you. Other than having the Primer lever all the way up when cranking it I am not sure how to give it more throttle as the forwar/reverse handle doesn't move with the Primer all the way up. Yes when warm it starts instantly, every time. Just need to get it to fire once and I then know it will eventually catch on.

Thanks,

[FNQCairns]

Yeah here lies the problem due to some throttles locking out the option to free rev, I am not conversant on all the yamaha throttle styles and what features they may have, someone may know them well?.

I bought a yamaha throttle that had the free rev option as it probably will save me from getting caught out one day, has already if I am honest.. I use it every time I start cold.

Your easy options are limited. the fact that someone has touched the engine means the tune has most probably changed, they do it the poor way all things considered and then leave the true cold start testing to the owner next trip. You could take it to be retuned with a little more richness added on each idle circuit screw etc etc who knows what they will actually do the options are large, or try again a different start procedure, say no-primer 2/3 spark advance lever and hope to stricke it lucky.

Still the major point is I would be hesitant in spending time pulling anything else apart or money on other parts as your problem should at best guess be the procedure.....due of coarse to the tune and/or previous idle time, fuel etc as above.

cheers fnq

[jimbo59]

Sounds like spark problem and i would be looking at the mob switch first. When i dosnt start next time try pulling the switch out with long nose pliers and turn the key.

[Spaniard_King]

Jimbo, did you read the whole post or just the first one:P

Dorado.. fnq has got it nailed ie " Starting Proceedure" As an engine gets older it will require a little more choke and throttle although the warm up lever should be providing adequate throttle for this.

Your engine requires choking when cold until it fires/coughs then no more choke but keep the throttle up. Is this how you do it??

[jimbo59]

[quote=Spaniard_King;945828]Jimbo, did you read the whole post or just the first one:P
Hey come on i just got up:D

[captain rednut]

carby clean and youll be back on the water in no time

[Dorado]

Jimbo, did you read the whole post or just the first one:P

Dorado.. fnq has got it nailed ie " Starting Proceedure" As an engine gets older it will require a little more choke and throttle although the warm up lever should be providing adequate throttle for this.

Your engine requires choking when cold until it fires/coughs then no more choke but keep the throttle up. Is this how you do it??

Hi Spaniard_King, the Yammy has a Priming lever at the throttle which under normal starting procedure you raise the lever fully and crank for 5 seconds, then lower the lever completely and crank again which is when it usually fires. There is no other choke as such and there is no way to increase the throttle at the startup via the forward/reverse controller. The engine wont even crank if the controller in engaged in for/rev, only in neutral. Only way I know to increase the revs is if somebody else manipulates it at the engine itself while I'm cranking it over at the helm. I haven't tried this yet as I'm alone at the moment and need a 2nd person to help me.

I also disengaged the kill switch just in case it is a problem with it shorting somehow and self activating but she still refused to fire up so I've reconnected it and I'll havta wiat til somebody gives me a hand I guess, soon hopefully. If not then I'll take it back to northside marine where it was serviced last and get them to fix it.....sigh*

FNQCairns, thanks heaps for your help too, I appreciate everyone's help here thanks.

Dorado

[Spaniard_King]

Dorado,

can you explain how the choke system works (not the throttle system) on your engine..just want to see if you are aware of how it actually works.

[captain rednut]

carby clean again

[Malcolm W]

Dorado, Not sure how the 70 works but my last 2 motors (115 yamie 2st) will only start with plenty of choke while cold(like all of the 2 st I have owned they love fuel). These have a key solenoid type and manual choke at the motor. Are you able to manually activate the choke from under the cowl. As above it seems you can rule out an electrical fault as it starts ok hot. Sound like she just needs more fuel.

[Dorado]

Hi Guys, thanks again for your help. This model Yammi is a 70hp 2st and it has an auto-choke. The start procedure I have followed for years now is as per the owners manual as I've described above. I took the boat back to northside marine today and the mechanic got it going. He first drained the carbs of fuel and then gave the fuel bulb a couple of squeezes and cranked the engine WITHOUT the Primer lever beiing raised and it fired immediately and ran well!!! He siad there may have been some bad fuel or crap in the carbs but he said never to use the Primer lever when cold starting (in complete contradiction to the manual and how I've been doing it for the last 16 years!). He also showed me how to manually emergency start it by manipulating the choke solenoid?? Anyway, he said give it some fuel conditioner and take for it for a good run today which I have now done and again tomorrow if possible (if it cold starts) and that may do the trick but if not, then a ful carb overhaul is probably needed - $500..ouch! He said NEVER to use the Primer lever unless the engine gets flooded cuz all it does is suck in air. So much for how I've been doing it by the manual all this time!!!

So here's hoping that tomorrow morning it'll cold start for me and I can again give it a good run, if not then I'm gonna lose $100 bucks worth of crab pots!!!

Thanks heaps!
Dorado