Tohatsu 9.8 2S newbie

[chipko]

Originally Posted by Fenlander

The only thing I have noticed with both Yamaha 15s is their pickup from idle seems a little cleaner on 80:1. But it's marginal.

Drive it like you’ve stole it and it’s sweet on 50:1

[Fenlander]

I know but our usual local launch means ten mins plus through speed limited moorings so I’m quite experienced in the just off idle feel. But you’re right, get in open water and all’s fine.

[chipko]

10-15 mins warm up at just above idle is a given for me every time, and yeah slight hesitation after extended trolling noticed. Soon pulls through it so not a problem. Two strokes just run so sweet when you get to 4500 revs and beyond.

[smallribber]

Steve.... I know you probably wont want to listen to me....... But you are over thinking this and worrying far too much. This outboard is a robust simple 2 stroke. Just use it and worry less. Most people just put them in the boot of their car anyway up. Mine are always handle up so it seems I have been doing it wrong for years but no harm has ensued. Treat it like an old shovel rather that your new best friend.

This post is intended to be helpful honest

[willk]

IIRC they had small metal protrusions or 'feet' just below the cowl rear face. They begged to be rested on, prop down. I packed mine that way

[Tommy c]

Originally Posted by Steve509926

Hi Tommy, hoping to get out next week to test the 9.8 with a 7.5 prop.
Is Windermere south of Bowness and on the West side relatively quiet so I can do some WOT tests? If not, it's back up to Ullswater.

Yeah you will be fine Steve.
You can park up and launch from the beach at harrowslack too.

[Steve509926]

Originally Posted by chipko

and yeah slight hesitation after extended trolling noticed

Hi chipko, so that slight hesitation is normal?

Originally Posted by smallribber

Steve.... I know you probably wont want to listen to me.......
This post is intended to be helpful honest

I appreciate it Dennis, it was the oil from the two small holes that concerned me, it just didn't sit right with my way of thinking. 2s are new to me apart from lawnmowers/chainsaws and, I had forgotten, my very first car - a Wartburg! so oil ozzing from any hole doesn't seem right unless it's Communist East German!

Originally Posted by Tommy c

Yeah you will be fine Steve.
You can park up and launch from the beach at harrowslack too.

Thanks Tommy, good to know. Harrowslack is where I tend to launch from.

[Steve509926]

Originally Posted by chipko

Drive it like you’ve stole it and it’s sweet on 50:1

Love that one chipko

[Steve509926]

7.5p prop (kindly loaned to me) fitted ready for a day on Windermere tomorrow.

Interestingly the blades on the Tohatsu 7.5p prop are 4mm wider than the "original"? 8.5p prop. Don't know what difference it will make.

[Fenlander]

I'd not really noticed that but yes in your pics it looks a little more towards the "paddle" style of a high thrust.

Also its diameter should be 0.4" less than the OE, not sure why that change.

[smallribber]

Do you think there is a danger of becoming a prop nerd

[Fenlander]

There is no shame in being a properly informed person on a technical topic. You are then a resource for those that would seek information.

Such as yourself "seeking" at 1709hrs on 23rd Sept 2023 when in a thread you asked for details of just the prop being discussed above as you may wish to buy one. Between us Chipko and I answered with the details that would enable you to do so.

So as the saying goes never bite the nerd that feeds you.

[Steve509926]

Originally Posted by smallribber

Do you think there is a danger of becoming a prop nerd

Yes, without a shadow of doubt

There is very little you can do mechanically to change the performance of either a 20hp efi Merc or the 9.8 2s Tohatsu. However, one thing that is relatively easy to do is make sure the correct prop is fitted to ensure you get the best out of your outboard/sib set up.

[Steve509926]

After my first outing with the 9.8 on Ullswater, I took a look at the spark plugs which were quite wet & oiled up. I cleaned them and reset the gaps, I also changed the fuel, as although the previous owner had said it was fresh, I don't know what ratio he had mixed.

It was a good day, if a bit wet and a little cold, on Windermere. The 9.8 started 2nd pull and the first thing I noticed was a reduction in the amount of smoke as compared to when I was on Ullswater. The OB ran much better and never missed a beat all day.

One thing that did come as a bit of a suprise (I know it shouldn't, but it did) was the amount of fuel used as compared to my 20hp efi Merc. I probably used a 1/3 more fuel.

One up, 12 ltr E5 @ 50:1 + kit, 7.5p prop

12.7 knots @ 5430 rpm at wot, 2nd trim hole 12mm packer, slight loss of grip in tight turns

12.2 knots @ 5430 rpm at wot, 2nd trim hole no packer, loads of splash over the transom.

13.2 knots @ 5490 rpm at wot, 3rd trim hole, no packer.

The 9.8 appeared to respond quicker and plane a bit earlier with the 7.5p rather than the 8.5p.
Very little loss of top speed but it's now operating well within the RPM range.

I took a look at the spark plugs when I got home. Very clean and practically dry.

[Fenlander]

Looks like your results are broadly in line with mine. For me the responsiveness to the throttle into the plane being the biggest improvement, particularly as we were two-up.

[willk]

Originally Posted by Steve509926

The OB ran much better and never missed a beat all day.

A tank of fresh premix and a plug 'service' covers a lot of bases. You're likely running at WOT a lot of the time which in a carbed stroker, will be sore on gas.

I've noticed a general reluctance (on the forum) to change plugs out or waste fuel. I've had a lot of success with it over the years, resolving poor running in a number of engines.

[Fenlander]

Yep re fuel particularly when the fuel mix comes with an OB and you can't be sure if the previous owner knew how to mix correctly.

Have the oily dribbles stopped now Steve?

[Steve509926]

Originally Posted by willk

You're likely running at WOT a lot of the time which in a carbed stroker, will be sore on gas.

Spot on willk, probably close to 80% wot which won't be the norm now I'm happy re: height & prop. Which reminds me, I must get the new prop ordered now the borrowed one is ready to go back to it's owner.

Originally Posted by Fenlander

Have the oily dribbles stopped now Steve?

Yep, no oily dribbles. I'm convinced it was because I transported it with the leg high on its back due to the Dole fins.

Re: Dole fins - free to a good home if anyone wants to give them a try. Drop me a PM

[Steve509926]

I'm tidying up the holes in the AV plate left from removing the Dole fins.
Filled, sanded and is now nice and smooth.
Question - would you spray with zinc primer first? Then dark grey undercoat before finishing with Aquamarine Blue top coat.
Or just the undercoat and topcoat?

[willk]

Personally, I wouldn't bring zinc anywhere near it - your alloy can't rust anyway. Primer and Paint for me. Make sure to remove or cover your anodes before you spray