4S Yammie problem

[Strewth]

My new 60 HP 4-stroke Yammie, with 50 hours on the clock, decided not to start on Sat when we were miles up a river in the middle of nowhere. :o After several minutes of furious cranking, and a few primes with the bulb, it finally chugged into action but suffered major power surges at constant throttle. Finally managed to get it up to full throttle and all seemed well. It started first time when we got back to the ramp and again when we got home to flush it. Any suggestions? My guess is a fuel blockage/problem, but motors were never my strong point. Have also noticed a bit of rattle at full bore, but am unsure if this is normal or not (tappets?).

The motor has only recently had its 50 hr service and never given me grief before. Am now paranoid about venturing too far afield.

Cheers

Strewth

[Jeremy]

since no one else has bit, my 2 cents...

If it was a blockage in the fuel system, your priming bulb should have been flat when you primed it after the motor stopped. If so, I'd give your fuel filters a good clean or even replace the filter units. After that, give it a run in close on your next trip and see how it goes. As long as you have a marine radio on board or mobile phone cover, you should be OK - if there are any problems you'll be able to call the VMR for a tow.

Jeremy

[DaneCross]

Sounds like you may have flooded it. Same thing happend to us recently. A guy once told me to disconnect/unclip the fuel line then kick it over a few times (i guess to get rid of excess fuel), then re-connect the fuel line and start her up.
Hope this helps.
Dane
P.S. I may be wrong, I'm no pro... you may have had some water in your fuel??

[Big_Kev]

Power surge is usualy fuel related and I would be checking the fuel filtering system.(ie: lack of fuel flow, since it continued to surge when up and running)
You should put a CAV type filter on with a glass bowl on the bottom for the water to be seen if you don't already have this.
The fuel filters under the cowl are not to big and a little bit of water in them will give you the probs as described.
Fuel blockage will have to be before the fuel priming pump for this to go flat as previously mentioned.
If you fill up at a cheap fuel stop or a station with old tanks you should also go elsewhere.
Cheap fuel has a higher chance of giving you a headache.
I always fill at the one station (new)that has a sign on the bowser qualifying the fuel, the cost is always higher but I figure I shouldn't have a prob either.
Other quick fix for this fault can be spark plugs, but they should give you more than 50hrs.
If no luck it will be a job for the dealer.
I run the same engine as you with 100hrs now and have not had a problem.
Cheers Kev.

[Strewth]

Thanks for the input. The general wisdom seems to suggest that it is a fuel problem. Have used the same bowser at the same petrol station before with no problems, so it's a bit of a mystery. Am about to inspect the fuel filters for water or gunk. I'm told that its normal for the tapetts to rattle a bit at full bore.

Cheers

Strewth

[jaybee]

had a similar problem last year, turned out the fuel line was sucking air at the outlet in tank. taped up the thread and tightened no more problems. could also be a small hole somewhere sucking air. I started at the motor and worked back to the fuel tank. hope this helps.
cheers
Joe