Outboard keeps dying on me

[QldKev]

I'd try with a spare tank and spare fuel line to start with and go from there.

I think this would be the best plan of attack. I have a spare tank you could borrow, but I'm in bundy.

If this proves a tank / supply issue I would try.
a) Check the tank breather, is it blocked? (sometime you will have problems when filling the tank in this case)
b) Crap in the tank blocking supply. Often hard to diagnose in under floor tanks.
c) Damaged / weak supply line. This could be a soft spot, kink, or even an air leak that gets worse when heated.

A few ideas.

QldKev

[the gecko]

thx guys, Im thinking the same things. Weve ruled out electrics , so it must be fuel supply.

My mechanic has loaned me a new tank and fuel line, and I will test this over the long weekend. I'll report back mid next week.

cheers
Andrew

[dreemon]

I've heard the check ball in the tank can be a hard problem to find,
when they have found it to be the prob they chuck it out,

[Bilopete]

Hi Mate,
I had a similar problem with my evinrude 12 months ago...I thought I was reading one of my posts actually! The problem was identified as a stuffed cdi unit. I have a Evi 35hp 97 model.

The change over cost me $500-$600 but it hasn't skipped a beat since BUT i have been warned that CDI's on mny model are notorious for cdi units playing up.

Cheers

Bilopete

[the gecko]

thanks to everyone who was following this post and made some input. After a bit more testing, I think its NOT fuel related.

I took a new tank and fuel line and kept it in the boat. When the problem started again, I took the old fuel line off at the cowling, and put on the new line and tank. Still got the same problem........bugger me. The carbys been cleaned out, and the plugs are new.

The mechanic has also 'loaned' me another cdi ignition unit, and that hasnt made any difference. Now Im really stuffed, so its back to the mechanic again. He reckons he will need to do a water test, but is confident he can find and fix it tho. He just didnt need to do the water test til Id done the fuel tank test.

Hmmm, the problem persists.....

cheers
Andrew

[FNQCairns]

Got any more info on how it does it, like never when cold, never from the ramp, never when going slow...anything really. I stayed out of this one because it didn't sound entirely like fuel if it does stop dead.

Any testing you can do can help like, starting it in pitch black with a spray can of water to mist the engine to look for light shows to when it plays up draining the fuel bowl to check the amount of fuel in there compared to it done at home with no problem apparent.

Sounds like a soaked heat/moisture problem (but I have no good idea just guessing like everyone else) what happens here is there is an electrical insulator crack somewhere, can even be hairline and indiscernible, as the engine heats up it increases upon any cool down it pulls moisture in. I have placed electrical parts in the oven to dry for a couple of hours then coated them while still hot with epoxy to seal...problem fixed...not all the time though.

I would consider some sort of short along these lines that in effect acts identical to your kill switch.

Next time before leaving home drown the entire powerhead and electricals in lanolin to exclude moisture and i mean drown, there is nowhere this stuff cannot coat and see if the problem persists. A single coils shorting out cable or even single plug cap short on cowl latch on a 2 cylinder can act as killswitch in practice, 3cyl not so much will stop pretty fast.

cheer fnq

oh yeah, is it forward control? if so don't forget all the ignition isolating bits and pieces up there.

[the gecko]

It always runs fine from the ramp on cold start. After it warms up, the problem starts.

At first, (last month), it was dying, and just needed a restart, and died again a few hundred metres away, restart, etc.

Now its got worse, and after a running fine for 5 mins from the ramp, it just goes down to 6kts on WOT. Its NOT running rough or lumpy, just slow. It feels like somethings caught around the prop and the revs cant get up (got a new prop tho and its spinning freely). So Im guessing that theres not enough spark or oxygen to let it run freely. It just runs really slow even with lots of throttle.

You could be right about a small crack or short somewhere.

cheers
Andrew

[FNQCairns]

Have you felt the heads/engine when it does it? might be retarded ignition timing due to an overheat or an overheat sensor playing up, it's premix i assume.

Guaranteed it might be very simple but with 20 potential points to check it becomes more difficult, even a trigger under the flywheel can cause all sorts of anomaly's depending on the model. A sticky needle and seat also but usually it will display a some warning just before the fuel runs out totally.

I would start with an overheat check, either a real or imaginary one, that last paragraph of yours does point in that direction.

cheers fnq

[CreelReaper]

Andrew,
This must be bloody frustrating mate. Doesn’t make for fantastic boating when the motor is unreliable.

To me there could be 3 possibilities…..
1) fuel
2) electric
3) kill switch

Now, if you have replaced all the fuel components and tank, has the mechanic checked the fuel pump? It could possibly be the diaphragm in the pump is pitted or has a hole or torn. This will subsequently leak ‘air’ and not allow you full bulb pressure or supply fuel pressure to the carbies. I am assuming that there is an in-line fuel filter just before the fuel pump.
When the motor stops, is the fuel filter full of fuel??


If there is sufficient fuel in the filter and line then I would be leaning towards options 2 and 3.

The mechanic has obviously checked the motor internal electrics and cdi etc. Is the motor electric or pull start?? Could there be a loose connection in the ignition switch or a broken wire that is earthing out??

It would also be not the first time I have heard of someone having trouble with the kill switch or wiring either. Is there a break in the insulation?? A loose wire, or a fault in the kill switch itself??

Hope you get this sorted quickly mate…..good luck.

Shane

[TJ Bear]

G'day

Was reading the info below on another site and thought it may be of help, never know.

E10 Fuel And The Untold Truth
I have been in a battle with my boat for 3 years to track down a fuel problem that up to a week ago was driving me crazy.I have a 6.5m allycraft centre consule driven by 2 merc 4 stroke 50's, and the problem was while driving offshore i would loose all power back to walking speed at full throttles, when i backed off it would stall and only start under full idle.

The first thing was to get carbies cleaned 3 times by 3 different dealers which helped for a short time but then same old same old.
Next i cleaned both my tanks out 5 times both tanks {150 litres each} now this was not fun through the sensor holes buit only got teaspoon of shit out of each tank every time.
I contacted Mercury all over the place asking for advise but noone could give me any reason for the problem.

Now after 3 years of this problem i was going to sell them but i couldnt let some other fisherman buy them and i hate getting beaten.

just happened into Caloundra Marine and was talking to owner about other things and mentioned my problem when he turned and gave me a sheet on E10 unleaded. Now i dont use E10 but do use normal unleaded to which he told me servos are putting E10 into normal unleaded.
This is the important bit:
E10 FUEL ONLY LASTS 14 DAYS IN YOUR FUEL TANK BEFORE IT SEPERATES INTO 3 DIFFERENT PARTS.
1} UNLEADED FUEL ON THE TOP
2}WATER IN THE MIDDLE
3}PURE 100% ETHENOL ONTHE BOTTOM.

And because ethenol in thinner the fuel it attracts water which sticks to it and travels into your motors passing through all filters and clogging your jets. So as he told me i was pumping [pure ethenol into my motors and then water mix and this was the cause of my problems. So i done some googling and found some really scary info. Just google e10 in boats problems.

so now i use premium unleaded only and to this day no problems fingers crossed so dont fall into the trap of putting normal or e10 unleaded in your boat tanks cause you will pay the price. I wil try and scan the sheet he give me so i can attach it to ths tread but anyone can pm me and i can fax it to you.

good fishing guys

[the gecko]

Well finally this issue has been solved. It turned out to be a faulty cdi/powerpack/ignition unit.

We were confused cos the mechanic 'loaned' me a second hand powerpack to try out, and I still had the problem. He thought he was doing the right thing, cos he didnt want to charge me $450 for the part, unless it fixed the problem. The loaner powerpack musta been on the way out too. A brand new one fixed the issue completly. Hooray.

thanks to all who gave suggestions. I love all the combined years of experience on ausfish.

cheers
Andrew

[Chimo]

Hi Andrew

Glad you finally got sorted.

I had the same problem with a 9.9 Mariner and after I stuffed around with fuel, plus etc etc I gave to the omc brp master technician who took a few minutes to diagnose that the bottom half of the power pack was stuffed. $300 for non genuine or $400 for the other one.

It would seem that half our problems seem to stem from the "service" we get from the boat mechanics out there.

Cheers
Chimo