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Old 22 June 2012, 14:59   #1
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First Outing

Evening All,
Had my first outing in my newly aquired SR4 earlier in the week and found couple of issues you may be able to help with.

Mariner 60 2 Stroke: Starts easily from cold (with an initial touch of fast idle). Happily ticks over in neutral, not too smokey and seems nice and smooth.

On muffs, allow to warm up, stick it in gear, low revs and all seems well.
In water, allow to warm up, stick it in gear and it stalls.
Having stalled it needs a big lift on the fast idle to fire up again. Stick it in gear before the fast idle revs drop off and its fine, off we go.
Im thinking idle revs needs increasing slightly? Before I get me tools out, any other suggestions?

Other issue is a real tendancy for the boat to pull left at about 50% throttle. Its easily corrected but took some getting used to, I'm thinking the boat is over powered and it feels like the prop is trying to steer, similar sensation to torque steer on a front wheel drive car.
Once up and running there is slight wobble left to right, corrected by lifting the prop slightly and reducing revs a little. Again could this be due to over powering the boat and/or a motor thats physically too big & heavy?

Cheers
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Old 22 June 2012, 15:13   #2
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Can't help you with the engine revs. However there have been many discussions about powering SR4s on here over the years.

They're rated for 50hp. Those that have been fitted with more have been described as fairly lairy - there is a marked tendency to "chine walk" at the top end - maybe explaining the side to side motion. The tendency to pull to one side might be corrected by adjusting the tab on the engine leg.

You should also experiment with moving some weight forward to combat the chine walk - a nice big bag of sand or gravel is a good tool.
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Old 22 June 2012, 15:17   #3
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You could also try adjusting the trim tab on the leg, it must be there for a reason so may as well see.
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Old 22 June 2012, 15:44   #4
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Maybe carburator and the fuel feed is to lean. Do a search on here as there has been many a thread on the subject. Mariners like the mixture on the rich side its better for the engine also.
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Old 22 June 2012, 18:02   #5
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Thanks for the replies. Chine walk is exactly what I'm experiencing and a sand bag up front is worth a shot.

Going to have a play with the mixture tomorrow
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Old 23 June 2012, 08:28   #6
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Sandbag is a good idea for diagnosis here, but if you find it does work to limit the chine walk I'd try to address the cause by fitting some tabs - smart tabs might work well. Otherwise you will just be burning more fuel to push round a sack of sand. Also bear in mind overpowering can impact your insurance as well as boat stability.
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Old 23 June 2012, 10:03   #7
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If the motor is requiring a lift on the throttle to restart it is most likely too rich, not lean.
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