Keeping speed to 5 mph

[chrissd330]

I have a 3.3 meter sib with aTohatsu 9.8 2 stroke,hoping to go on llangorse lake where there is a 5 mph speed limit,question is will my Tohatsu run slow enough,it will also be my first time out.
Chris

[Mickhitchuk]

I have the same motor on a 3.1 sib and have had no problems running it on low revs, it's a bit lumpy on tick over but I guess you will be just under quarter throttle at that speed on a flat calm lake, I guess if the plugs do start oiling up you could put it in neutral and give the throttle a quick blip

[Fenlander]

Personally I've never had a problem with 2-strokes oiling up. I use a quality oil and mix exact proportions. Also make sure plus are the right spec and gapped property plus idle mixture set correctly.

Over the years I've used Mercury/Mariner 15, Tohatsu 9.8, Mariner 8, Suzuki 8, Suzuki 3.5 & Mariner 2 two strokes on local 4-6mph limit rivers for hours at a time. Never considered oiling up at tickover or restarting an issue.

So have confidence it will be fine... worry about it and it might happen!

[willk]

What Fenlander says above would reflect my experience with the 9.8 as well. I was very fussy about the mix (50:1) and used good oil. I'll go out on a limb here and suggest that if you are restricted to lower revs for long durations and are worried about oiling/smoke, you could consider using a leaner mix - say 75:1 while on the lake. IMHO the 50:1 standard is there to provide lubeing at max revs, not trolling speeds. I knew a bloke who ran his 9.8 all the time on 100:1 (as he insisted this was correct ) and it seemed to be running fine for him after a few years. He appeared to use it for fishing most of the time so that might explain it.

[chrissd330]

Thank you all for your help,not used it before,first time out,better on a lake than out at sea.will probably only use it for an hour or so.Next time should be at Dale Pembrokeshire.
Was worried it might not go slow enough but 1/4 throttle sounds fine

[HDAV]

Unlikely anyone will be out with a radar gun so just keep it gentle....

How they manage to water ski round there at 5mph I'll never know

[Pikey Dave]

Could always put a lower pitch prop on, if you have one handy.

[Mikefule]

On the whole, 2 stroke engines thrive on revs. However, I used to use my 2 stroke 9.9 and 15 on the river on a small SIB.

It is unlikely that anyone will strictly enforce 5 mph, as opposed to, say, 6 or 7 mph. The important things will be:

1) Planing will obviously attract attention.
2) Towing a big wake will attract attention, especially near moored boats, delicate shorelines, and any other sensitive environment.


Keep to immersed speeds, keep the speed down, slow down when you approach other boats, and don't worry about the number 5.

The engine will be fine. If in doubt, you can click it into neutral every few minutes and rev it for a few seconds.

Alternatively, if you're going to do a lot of boating where there's a 5 mph limit, think about getting a 3 hp egg whisk. Lighter, easier to carry and store, and no need for a remote tank taking up floor space. I loved mine and now regret selling it.

[jeffstevens763@g]

Modern two stroke oil doesn't oil the plugs up its designed not to, we run our two stroke all day on rivers just ticking over never a problem.if worried take it out of gear now and then a give it a few revs.

[Bigplumbs]

Just give it a blip now and then it will be fine. I also tried out my (new to me) Tohatsu 9.8 yesterday and was very pleased it will tick over all day in my view but as other have said get the mixture right


Dennis

[chrissd330]

Lots of interesting info there especially the plugs not oiling up,did like the 3 hp egg whisk,would a 3hp 2or 4 stroke engine move my 3.3 meter sib with 2 adults in,be allright to carry as a spare in case the main engine fails or if I go on Ullswater next year.

[Mikefule]

Originally Posted by chrissd330

Lots of interesting info there especially the plugs not oiling up,did like the 3 hp egg whisk,would a 3hp 2or 4 stroke engine move my 3.3 meter sib with 2 adults in,be allright to carry as a spare in case the main engine fails or if I go on Ullswater next year.

My current SIB is 3.1 metres and will chug up stream on the Trent under the power of a 1.5 hp electric motor. However, that is definitely underpowered.

My previous SIB was about 3.3 or 3.4 metres (I bought it 2nd hand and can't remember the exact length. I know it had larger diameter tubes and was longer than my 3.1.) I used to go out solo on that with a set of dive gear, anchor box and so on with a 3 hp 2 stroke on sheltered coastal water. I once did 24 miles in a day with that set up. I also took it on rivers with 1 or sometimes 2 passengers.

3 hp is 3 hp whether it is 2 stroke or 4 stroke.

Everything to do with SIBs is a compromise between portability and capability.

On the water, we'd all like another half a metre and a few more horsepower.

When carrying it or storing it, we'd all like to save a few Kg and a bit of bulk.

I personally found 3 hp a nice size for sub-planing speeds. Anywhere it the 3 - 6 hp range will offer a different balance of performance and portability.

[chrissd330]

Hi Mike that looks good , just what I need 3 hp,most of my trips will be less than half a mile out in a sheltered estuary on my own a 3hp 2 or 4 stroke with built in fuel tank and less than 20 kilos would be much easier.
I can still keep the 9.8 2stroke for when there's 2 or 3 of us
Chris

[lightning]

I have trolled on the canal for hours with my 2.85m SIB and Tohatsu 9.8hp two stroke.

I use a 50/1 mix and it's never broken down or cut out. It is a little lumpy at very low RPM but the rubber mounted power head isolates the vibration from your hand on the tiller.
lt's certainly better than my previous engine, a 6hp four stroke which made my tiller hand go numb after a couple of hours.

[chrissd330]

Hi lightning,thanks for that ,very useful.
Chris