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fishing111
04-03-2011, 08:50 PM
Hi there, anybody got any ideas as to why a white Suzuki 115 4 stroke would keep stalling at 700-1000 RPM, and less occasionally at higher revs? It has been doing it periodically now for quite some time which is pissing me off big time as I have to keep continually checking the bulb is hard when trolling close to land and driving boat on trailer. The motor has also stopped at higher revs, surging until it dies, but usually it is at just above idle.

When the motor stalls at low revs it sputters and vibrates until it stops, and then I have to pump the bulb to hard and then its right again for the next 10 - 20 minutes. I am thinking that maybe it is something to do with the humidity, or possibly the fuel pump, or vapour lock of some sort but don't really have a clue. The motor has just had its 100 hour service and I told the mechanic but he said nothing showed up on the print-out. I have changed the primer bulb over, and thought that cured it until the problem resurfaced recently. I always use fresh fuel and there has been a Racor fitted since new, and the vent is incorporated into the Perko fuel lid, and is not blocked. To my way of thinking its fuel starvation of some sort, similar to when you forget to undo the vent on a portable, yet it happens periodically at higher revs and all the time at idle, so I don't know.

Cheers for any ideas.

Spaniard_King
04-03-2011, 09:53 PM
Had these symptoms before... take the idle air control valve off.. last time the O-ring seal was crushed and not seating correctly causing the engine to surge and run rough especially at idle....140 suzi it was.. basically the same as the 115

fishing111
04-03-2011, 10:00 PM
Thanks for that Gary, i'll pass that info on.

finding_time
04-03-2011, 10:26 PM
Garry's all over it as usual!! A mate had a similar issue with his Yami 115 it was a crushed o-ring on his idle air control valve!

Ian

fishing111
05-03-2011, 06:01 PM
Gary if I gave the mechanic the information I supplied here prior to 100 hour service, would it be an easy diagnosis for the mechanic to find, or would it be something that not many mechanics would know about, assuming that it is a misaligned/crushed o ring seal? The question is not coming off right, basically wanting to know if these are rare events, or something that should have been picked up by your average everyday authorised Suzuki mechanic.

Spaniard_King
06-03-2011, 06:42 AM
Paul,

These sorst of problems require some lateral thinking. If the compression is good and even(I assume that he would have checked this) and the fuel system pressure is steady and new spark plugs fitted then it has to be some sort of air leak into the inlet manifold between the throttle body and the cylinders this will be making it difficult for the Idle air control valve to keep a steady constant idle. As the idle air control valve is a bolt on item I would start there... it may only need cleaning but its one of those boxes that needs ticking;)

fishing111
06-03-2011, 11:32 AM
Thanks for that Gary, hopefully next time you can do the service.

aspherious
20-03-2011, 08:21 PM
Hi everyone
there is an inherent problem with the suzuki motors once they have been run for some time on a warm/hot day with the fual vapourising and vapour locking. i dont know if suzuki australia is aware however suzuki usa do. there a few fixes that appear to work, one is to install an inline fuel pump, the other is to install some kind of liquid cooling.

please find the following link
http://www.carolinaskiffowner.com/showthread.php?7213-Suzuki-DF-115-problem

the same problem has been described in detail and some solutions given even some photos of their fixes.

no chicken tonight
21-03-2011, 06:05 PM
Before you go any further with the outboard, eliminte any chance there may be a problem elsewhere. I had a similar prob. Got a remote tank and another fuel line directly to the outboard. Problem gone. Found a pin hole in fuel line where it was drawing air instead of fuel. Worth a try.