Outboard starting problems

cueball

cueball

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Hi all,
The outboard in question is a 2010 4 stroke Yamaha 9.9 high thrust electric start.
When tilted and out of the water she will crank and start but when vertical (in running position) she will crank but won't start, If I start when tilted then place verticle she stalls! I am baffled!
Any suggestions?
Thanks in anticipation
 
I reckon you have a wire that may be badly chafed and is shorting out. There’s a loom that usually goes through at the aft of the engine, near the mounting bracket, and this can sometimes get pinched, so I’d start my investigating there.

VicS is probably the best to advise. I’m sure he’ll spot this post and respond soon.
 
Thinking at the moment

If any wring is flexed when it is tilted KAL's suggestion is one possibility worth looking into and certainly if it suddenly stops dead rather than slowly dying

If you are saying that it dies as soon as it is tilted down into the water I am wondering about the immersion depth. I believe the high thrust 9.9 only comes in long ( 20") and extra long (25") shaft versions intended for on smaller sailboats and the American style pontoons. I am therefore wondering what type of boat you are using it on. Presumably not the MG 353 you had 18 months ago nor the Dehler 41 you were think about buying, but not the Avon Redstart you were wanting a bracket for surely ?

If you are fitting it, esp if its 25" shaft model, to a small dinghy then maybe the back pressure on the exhaust is the problem ???????

Alternatively if it dies a little after being tilted down perhaps a problem with the carb or fuel flow.

A little more information on the way it behaves , the exact model and the boat it is fitted too would be appropriate.
 
Hi thanks for the replies,
The boat is a prout sirocco 26ft, the engine is the long shaft with an Extention making it extra long. Mounted on the central nacelle.
Engine is fairly new to me pre season. Has been working fine 5/6 hours so far.
Went for a sail yesterday, engine started fine, as soon as clear of the marina and sails up engine goes off an I tilt her clear of the water to reduce drag.
On returning I was fighting an progressively stronger ebbing current and reducing wind so decided to motorsail. Dropped the engine and again she started. 200 yards from home she died, on cranking couldn't restart.
Dropped the anchor and sails for a closer look
Went through the usual, fuel, primer bulb, valve open, filter blocked, lanyard attached all good!
Then I tilted out of the water as flow increasing. Popped a spark plug cap off to check spark and she started on one cylinder. Replaced cap and she was running.
Returned to upright and died again
Went through this process a few times and the same happened.
Model is FT9.9GE
 
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cueball said:
Hi thanks for the replies,
The boat is a prout sirocco 26ft, the engine is the long shaft with an Extention making it extra long. Mounted on the central nacelle.
Engine is fairly new to me pre season. Has been working fine 5/6 hours so far.
Went for a sail yesterday, engine started fine, as soon as clear of the marina and sails up engine goes off an I tilt her clear of the water to reduce drag.
On returning I was fighting an progressively stronger ebbing current and reducing wind so decided to motorsail. Dropped the engine and again she started. 200 yards from home she died, on cranking couldn't restart.
Dropped the anchor and sails for a closer look
Went through the usual, fuel, primer bulb, valve open, filter blocked, lanyard attached all good!
Then I tilted out of the water as flow increasing. Popped a spark plug cap off to check spark and she started on one cylinder. Replaced cap and she was running.
Returned to upright and died again
Went through this process a few times and the same happened.
Model is FT9.9GE
Click to expand...

So was running OK but died.

Fuel flow problem maybe esp if it died slowly

Ignition porblem if it suddenly stopped dead. Do you use a kill cord ? Probably not on that type of boat ?
 
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have you tried running it vertical out of the water? If it runs out of the water then you have isolated the problem to exhaust partial blockage or back pressure issue.
Obviously dont run it for ages dry. maybe you could try it with an earmuff too
 
cueball said:
Yes she has a kill cord on the remote. I'm thinking fuel problem as everything works ok tilted
Click to expand...

I am leaning that way too.

Check the fuel line, esp the connectors for (air) leaks

Try pumping the primer bulb to see if it will keep going ?????? but if the carb bowl is filled OK it should start and stay running for a while even if no more fuel gets through.

I think its important to check for good sparks. Certainly before tearing into the fuel system
 
VicS said:
I am leaning that way too.

Check the fuel line, esp the connectors for (air) leaks

Try pumping the primer bulb to see if it will keep going ?????? but if the carb bowl is filled OK it should start and stay running for a while even if no more fuel gets through.

I think its important to check for good sparks. Certainly before tearing into the fuel system
Click to expand...

I had fuel problems on my Yam 9.9. There was a slight split in the lift pump diaphragm. The test is to pump by hand using the bulb. If this keeps it running there is your problem.

I don't think it being deep in the water that is the problem. Mine was very deep in & it never complained. They have an idle exhaust relief port anyway. When idling no exhaust comes out under water, it all comes out the relief port half way down the leg.
 
What might worth me is that when I’m down position and not running, it would suggest that the back pressure of the water is either having an effect or that when in this position it is pulling water round the engine. The first on an old two stroke would mean the crank oil seals are away. Not sure on the 4 stroke. The second might suggest that the water being circulated might be seeing ingress to where it shouldn’t.
 
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