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1992 Yamaha 70 BETO L Wont Start

dorado

New member
"Hello, I have owned the above

"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"
 
"Toney, first step is to posit

"Toney, first step is to positively identify if it is a fuel or ignition related issue. Could be as simple as an ignition switch starting to act up. Working sometimes and not others. Working in the crank postion but not always in the run postion. Start looking at the cheap stuff first. The switch is 16 years old and is exposed to the outside environment."
 
"Hi Rollie, thanks heaps for y

"Hi Rollie, thanks heaps for your assistance. Where would the ignition switch be in the engine or is it in the housing where the key is? I am not 100% certain that the problem is not fuel related but I checked all the lines and the fuel is flowing fine. To me it's as if the red man overboard curly cord has disengaged from the connector and activated the kill switch. I say this because the engine cranks over but doesn't fire at all exactly as if the kill switch has been activated with the red curly cord removed. Perhaps it is self activating somehow? Is this what you mean because this switch is definately exposed to the outside environment being just below the key?
Thanks,
Toney"
 
"Toney, the ignition switch is

"Toney, the ignition switch is the key switch, it is also possible for the safety switch to short across as well, have seen both cases before. I've been lucky in chasing these problems as I have access to a mechanic and friend at the local shop. I just borrow another control box and harness, plug it into the engines harness conector see it that solves the issue. If it isn't, at least I've eliminated it for good."
 
"Toney, your starting procedur

"Toney, your starting procedure from your first post. Do you keep the fast idle lever up while you crank it over, or not? I have always primed the fuel line bulb until hard, then lift the lever up (leave it up) push in the key to choke as I turn the key. Once it fires I quickly drop back the lever to keep the rev's from being too excessive. Keep it running by bumping the choke until it runs without it. Let it idle until the temps up then ready to go. The only time mine will fire without fast idle/choke assist is when warmed up and is restarted shortly after having run."
 
"Rollie, Yes the start up proc

"Rollie, Yes the start up procedure is exactly as you describe except that the Yammy doesn't have a choke function, i.e you do not push in the ignition key to choke, just raise the Primer lever up fully, turn it over, lower the lever and crank it again. That's how I've done it all these years now and it's fired each and every time without exception!

Just in time...your post.."Sounds like there is varnish

you run a stabilizer"

Can you be more clear please? What do you mean by varnish? And what do you mean by a stabilizer?


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,
Toney"
 
fuel stabilizer

varnish in


fuel stabilizer

varnish in the carbs from gas sitting over 6 weeks

well now you test compression and spark
 
"Toney, still sounds like an i

"Toney, still sounds like an ignition related problem to me....as you aren't getting even a bark out of it trying to start. Could be the black box going. have you tried giving it more throttle while you crank it over? As the engine was in for service recenty, maybe they have adjusted the cables and your not getting enough open throttle with the lever. Pop off the hood, go through the normal start up routine but then hold open the throttle at the carbs while someone cranks it at the key. Do this just to see if you can get some kind of response out of it trying to fire. If not then it really starts to look more like ignition."
 
"check compression, spark and

"check compression, spark and fuel

simple

i still say fueling, because over the years i have never seen a bad box yet"
 
"The kill switch is ground act

"The kill switch is ground activated, I believe if you just disconnect the wires from the switch and leave them off (open circuit) it should fire up."
 
"the 9.9 timing began jumping

"the 9.9 timing began jumping all over the place, ran but spead up, then almost quit, backfired, coughed then ran fine for a bit..repeat...the 115 would just quit, as if the key was switched off, would not re-fire immediately, then after a time it would start up and run as if nothing happened, fine for a day or so, then act up again...trouble was getting it to quit at the shop so they could pin it down so I wasn't buying the wrong non-returnable parts...I stayed in the yeard on the hose until I got it to quit"
 
"Hey guys, thanks so much for

"Hey guys, thanks so much for the good advice. I will try all this and get back to you asap. I did check the spark on all 3 cylinders and there was enuf to give me a good belt 3 times. Also fuel is flowing from the bulb, when I squeeze it, thru to the engine and into the small fuel bowl within the engine compartment. One thing I did notice on the fuel bulb is that there is a direction arrow on it which funnily enuf is pointing away from the engine, not towards it. Would this matter as it did start the other day. I would've thought that the direction arrow on the bulb should indicate fuel flow towards the engine. I have never mucked around with this and I am thinking that when the engine was serviced and they replaced the big fuel filter located just after the bulb that they may have switched this around by mistake???

I am not sure how to do a compression test nor have the equipment to do it. My battery is now fully re-charged again so I am about to chuck it back in and crank it up again. Thanks,
Toney"
 
"Okay. Well I switched that bu

"Okay. Well I switched that bulb so that the arrow is pointing in the direction of fuel flow to the engine. On doing so I tried to pump it up but it refused to pump up at all and just wouldn't work so I swithced it back to how it was and it pumped and got nice a hard. I primed the lever and cranked but no start. Closed it and cranked, same effect. I then disengaged the kill switch and gave it another crank with the lever up, then down but she still refused to fire!! Running out of options other than to somehow increase the throttle at the engine whith another person's help while I crank up at the helm. There is no other way I know to increase the throttle on my own. AFAIK it can't be done at the forward/rev console as the engine will only crank with it in neutral. I'll try to get some assistance from a mate and do as you suggested Rollie - to increase the throttle at the engine while I crank it at the helm. Failing this it's back to the mob who serviced it last and try to get them to sort it out.

Many thanks,
Toney"
 
"Toney, there must be a hidden

"Toney, there must be a hidden loop in the fuel line and it was hooked up to the engine line all along...otherwise it will be pulling fuel from the engine"
 
"Hi Rollie,

thanks again fo


"Hi Rollie,

thanks again for your help. You're right on the money mate. The fuel did in fact have a hidden loop and it is pumping in the correct direction. Okay, well, 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 being raised and it fired immediately and ran well!!! He said 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 full 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!!!

Cheeers,
Toney"
 
Good to hear its running. Kin

Good to hear its running. Kinda confusing when your getting told 2 different ways of properly starting you engine. What ever works I guess. Mine you have to give it throttle or your just heading towards a dead battery from endless cranking. So long as a method is consistently the same so you have confidence that if it won't start after your normal routine that you need to stop and look for something that you forgot. Hope the carbs are ok.
 
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