Thread: Duck boat outboard tips

Originally Posted by mimms2

As said, good fuel, clean oil. New and gapped plug.
Also check/gap your magneto, I assume it has one.

Check for vacuum leaks around carb gaskets/boots - squirt a bit of CRC66 at them while it's running: if the motor picks up - you're sucking air and any other tuning is going to be chasing your tail.

Two and one-half turns out is a good starting point for all carb screws. If the carb has an idle-circuit that will probably be it, and you'll tune your top end for best performance/economy wherever you want it (trolling, or travelling?)

I'm gonna have to disagree with VC, 2 toke oil is 2 toke oil. But I'd go for motoX or stihl, rather than budget lawnmower stuff. You mix to the OIL specs not the MOTOR spec (oils have improved a bit in the last century) but you're always better running more than less.

There was a diagnostic method on the old 2T racing bikes called "plug chop" - not sure if I'd do it to an outboard though. Run it at the problem load/revs, then cut the ignition. The condition of the spark plug will tell you what's wrong.

We will have to agree to disagree then.
Outboard oils only should be run in outboards.
It is less lethal to aquatic life and is less polluting.
It burns cleaner at lower tempratures to keep the plugs, pistons ,head and exhaust from carboning up.

Always mix to the ENGINES mix ratio not the oils, the oils 100 or 1000 to one rating is its maximum in engines designed for lean ratios.

If you mix 100 to one for a seagull designed to run 30/40 at ten to one it will seize its plain bearing in no time at all.

50/1 is the correct fuel for that outboard. A easy way to get your ratio is to double you fuel fiqure, and then move the decimal point to the left add a zero at the end and presto there’s your ratio. I.e 13ltrs of petrol double the figure =26ltrs move the decimal point to the left and viola there’s your mix ratio .260ml of oil.

Yep mixed it at 50/1,what’s the cause of this?had it running and warmed up in the tank and when I removed it noticed this..any ideas team?

Have you damaged the seal when checking the waterpump?

check leg oil level and condition for water or loss of oil.

The oil looks very black as if it is actually from exhaust but that is extreme amounts.

Originally Posted by veitnamcam

Have you damaged the seal when checking the waterpump?

check leg oil level and condition for water or loss of oil.

The oil looks very black as if it is actually from exhaust but that is extreme amounts.

Mine does the exact same thing! Gearbox oil it isn't, so it has to be from the exhaust blowing through the leg/gearbox joint. Perhaps it's normal as we usually just use muffs for the Jap makes and no dirt bin?

Originally Posted by outlander

Mine does the exact same thing! Gearbox oil it isn't, so it has to be from the exhaust blowing through the leg/gearbox joint. Perhaps it's normal as we usually just use muffs for the Jap makes and no dirt bin?

Yea its extreme amounts tho.... possibly from running chainsaw oil rather than outboard oil.
A tank or two of the wrong oil either way (saw oil in outboard or outboard in saw) is no major problem but continued use will drastically reduce engine life.

Sent from my S60 using Tapatalk

Originally Posted by veitnamcam

Yea its extreme amounts tho.... possibly from running chainsaw oil rather than outboard oil.
A tank or two of the wrong oil either way (saw oil in outboard or outboard in saw) is no major problem but continued use will drastically reduce engine life.

Sent from my S60 using Tapatalk

Well, that's a relief VC. It's a new (to me) motor so only ran it once and it was with Silkolene Comp 2 synthetic oil for two stroke bikes. I sure that's what caused it.

That might be it ,I used 2 stroke stihl oil,have some proper outboard oil for my 50hp so will give that a whirl,just replaced leg oil with new gear oil so don’t think that’s it.

The bin I’m using is only just big enough to fit the lower part of the engine in as well so might make it look like excessive amount of oil?gonna try an give the carb a clean tomorrow,might help?

Originally Posted by The bomb

The bin I’m using is only just big enough to fit the lower part of the engine in as well so might make it look like excessive amount of oil?gonna try an give the carb a clean tomorrow,might help?

It's got to be the 2 stroke oil, that's our common denominator. I've previously run both a Yamaha 30 and an Evinrude 115 on muffs and proper outboard oil with no oily evidence on the lower legs before.

Looks like that was the problem,rigged up the hose direct to the intake on the leg this time and no issues,there is 2 small holes at the lower front of the leg just under the seam where it bolts together which seem to be another exhaust exit along with the main pipe lower down..yeehaa ready to go for opening morning now..not that I’m holding onto much hope it will go ahead this year..

Originally Posted by The bomb

Looks like that was the problem,rigged up the hose direct to the intake on the leg this time and no issues,there is 2 small holes at the lower front of the leg just under the seam where it bolts together which seem to be another exhaust exit along with the main pipe lower down..yeehaa ready to go for opening morning now..not that I’m holding onto much hope it will go ahead this year..

Not sure what you found...was it the small quantity of water in the bin, or the wrong oil? The two holes you mention are tiny in comparison to the amount of oil spewed.

Both I would say,used stihl oil for the first 50/1 mix, and the when I used the muff setup noticed the 2 small holes pumping exhaust,hadn’t seen them before as they were under water in water bin,also cleaned the carby out yesterday so it might be running cleaner now,think the small water bin might have added to the appearance of all the oil on the leg as I lifted it out it would have picked it up from the surface..

Will give the proper outcome oil a go tomorrow probably

I cant count the times I have been told about a fire on a boat when its just a OMC ( Outboard Motor Company) starting up. I do know the the OMC were absolutely notorious for over oiling on start up. A system designed as a safety factor for the motor. Yeah rite. Certainly on the V R O ones.