Thread: Duck boat outboard tips

Just managed to get a great deal on a 12ft parkercraft and an older(early 80s)7.5hp Johnson outboard,have painted the waka and replaced the plugs and put fresh fuel in the tank of the outboard,got her fired up and running but bit rough,what’s some other things I can do to improve the running of the motor?have googled a bit and seen that a new impeller and to change the oil in the bottom of the shaft is recommended??any other ideas for the old girl? Thanks team.

Wow she looks great. If it’s running but rough, the new plug could be suspect or you will need to flush the carbs and fuel line. Should of given you my other one to camo, that’s a fantastic job.

Do you know its history?
If not change leg oil and replace impeller for a start.
Without actually being there to hear it run it is impossible to diagnose anything but.

drain float bowls.

If it starts and stays running reliably after changing leg oil and impeller give it a good run in a bucket or on the muffs untill well warm, telltail should be warm and 6year old stream not 60year old stream.

Fuel mix should be 50/1 of fresh fuel and a outboard oil not a chainsaw/lawnmower oil.... mine seems to prefer 95.

Of that vintage it may have a mixture screw on the front with the choke and stop button....it can take a while to really get this dialed in so idle is reliable if it has been sitting or titued with.
Only adjust it after at least 5 min running at or near full load to clean the plugs and be at operating temp....once dropping to idle if slowly idle drops and or it 4strokes idle is too rich, wind knob clockwise (tighten) to lean out. If idle increases or surges and is ting ting tingy its too lean adjust knob out anti clockwise.
If all good get out and burn a tank of gas on the water( in walking or rowing range) some full throttle hours does wonders for old two smokes

Hardcase,download image is right way up.
Nice paint job

Also the tell tail has water pumping through it but not a powerful stream..

Yea considering she was BRIGHT orange it came up pretty good,Had it in at Kings marine here in Hamilton for a proper overhaul but rushed in today and grabbed it back as I want it up and running for opening day if it goes ahead that is..bloody lockdown..only thing I can see missing is the tilt adjustment bar thingy so won’t be able to hit reverse or the motor will end up in my lap..

Originally Posted by The bomb

Also the tell tail has water pumping through it but not a powerful stream..

If impeller has been replaced that is a concern, engines sitting unused and not well flushed can build up "salt" but is actually aluminium corrosion.
First poke a bit of 200-300p mono or a bit of tig filler wire or what have you up the teltail hole while running.....if a few pokes clears it you can rest a bit easyer that it is getting water but I would check thermostats are working and not blocked.

Haven’t replaced impeller yet as no parts available due to lock down,it’s on my to do list when things get back to normal,has a lean/ rich adjustment lever on the front by the choke so will give that a go once motor is warmed up,will try the mono trick as well,what oil do I use in the leg?

you could also try high octaine fuel.....my older 6hp merc came to life when fed the good stuff,as do chainsaws and mowers....the 98 from BP is great.
tilt bar thingy.....piece of cake...ball cock arm will fit.not at one end and bend the other....or any long enough bolt that will fit..... the angle of your dangle will make HUGE difference to how it pushes along under a load of guys n decoys.
possibly only one hole off bottom will work.
now you have boat n motor,the big weekend will be so much fun...I spend a lot of time and too much petrol (but we wont go there apart from to add oars are good) zooming around lake to stir up birds from the centre and picking up wayward decoys and picking of woundie birds....if the choose to dive rather than fly 3 times they die...

Originally Posted by The bomb

Haven’t replaced impeller yet as no parts available due to lock down,it’s on my to do list when things get back to normal,has a lean/ rich adjustment lever on the front by the choke so will give that a go once motor is warmed up,will try the mono trick as well,what oil do I use in the leg?

80/90 gear oil....standard automotive gear oil is fine.

Yea looking forward to not having to paddle the Canadian canoe this year, will keep that for drifting small streams,no dog this year either since the pointer cashed in his chips late last year..will give the 98 gas a go as well.

It's also important to check the compression. I have a 1995 Johnson 8hp and the top pot measures 120psi and the bottom 110psi. Closer they read to each other the better, with a minimum reading of around 80psi as a limit. My advice is to use 95 octane mixed at 50:1 and TC-W3 two stroke oil. I recently tried Silkolene Comp 2 oil from my race bike and found that it spat oil mix and smoked excessively at 50:1.

Only use TCW3 oil as it is designed for water cool motors not air cooled ones. Never seen salt water that I’m aware of, it has been some time since last started.

Replaced the gear oil and pulled and checked the impeller,blades look in good knick,got her back together and definitely pumping water better through her now,gonna mix some proper outboard 2 stroke oil instead of the stilhl stuff I used,have some for my bigger boat,really wanting to get to a lake and give it a good run to really see how it goes..starts second pull every time now..🤞will try the hi octane gas mix as well..appreciate all the advice..

I bought proper outboard 2 stroke oil and then mixed it will stihl stuff...LOL boat seems to work well with it,no excess smoke and starts good...15hp t stroke merc..... the 6hp 4 stroke merc was a dream to start on 91...not so flash on high octain but the difference at high end revs was measurable on gps....very measurable eg 3-5kmph more.