Naughty Outboard

[Snowgoose-1]

My Tohatsu 4 stroke runs nicely. Tickover fine for while then lowers revs and cuts out. Just when coming into berth.
Have renewed the two throttle cables and throttle stop carburettor ok. Fresh petrol and new in line paper filter . Thanks for the any replies.

 

[fredrussell]

Just about all small outboard woes are, in my experience, due to carb jet blockages. I’d start there.

 

[Refueler]

I assume that when throttle is above tock-over - it continues running ok ?

If so - then it points to slow running jet or set-up.

 

[RAI]

Try a new spark plug.

 

[Snowgoose-1]

Thanks for the helpful replies.
Although I start out with a new spark plug teach year , I did not check the gap. Instead of 0.35 it was nearer 0.45. That plus the suggestions seem to have resolved issue. Thanks to all.

 

[Mister E]

Are you using e10 or e5 fuel?
If you had old fuel in there then started the engine you might have clogged the carbon.

 

[Snowgoose-1]

Are you using e10 or e5 fuel?
If you had old fuel in there then started the engine you might have clogged the carbon.

Good point.
I'm currently using fresh Esso Superunleaded which iss ethanol free in my area. Even my lawnmower likes it. The Briggs and Stratton has a beautifully simple fuel arrangement . The fuel pump is a simple diaphragm gasket with ingenious flaps for control. Apologies for thread drift.

 

[VicS]

Good point.
I'm currently using fresh Esso Superunleaded which iss ethanol free in my area. Even my lawnmower likes it. The Briggs and Stratton has a beautifully simple fuel arrangement . The fuel pump is a simple diaphragm gasket with ingenious flaps for control. Apologies for thread drift.

Ay present, but will contain up to 5% ethanol from September

From Esso's website

​

What’s in our Synergy Supreme+ 99 premium petrol?​

Our Synergy Supreme+ 99 petrol has more cleaning power than our regular petrol – and includes molecules engineered to reduce friction in your engine and help moving parts work more efficiently.**​

We currently supply an ethanol-free Synergy Supreme+ 99 unleaded in some parts of the UK. From September 2023 our Synergy Supreme+ 99 will transition to contain up to a maximum of 5% ethanol at all Esso pumps irrespective of which part of the country they are located. The labelling at our pumps will remain as E5 for Synergy Supreme+ 99 unleaded.​

 

[QBhoy]

I bet it’s taken oil up and into the carb. Had the mercury version. Famous for it. No matter what side you sit it on.

 

[Snowgoose-1]

Ay present, but will contain up to 5% ethanol from September

From Esso's website

Good while it lasted I suppose. Alternative could be Aspen which does not contain ethanol. Did a search on this website and it has mixed reviews for the outboards.

 

[Refueler]

Good while it lasted I suppose. Alternative could be Aspen which does not contain ethanol. Did a search on this website and it has mixed reviews for the outboards.

This is a personal opinion ... not worth the extra cost.

I run all my garden gear ... tractors .... cars .... outboards on 95 (E10) and have no trouble ...

 

[Snowgoose-1]

This is a personal opinion ... not worth the extra cost.

I run all my garden gear ... tractors .... cars .... outboards on 95 (E10) and have no trouble ...

I think the issue has more to do with lifespan than performance. It's suggested that carbs should be drained if left for three three weeks. Until ethanol, I could leave petrol in a mower all winter without problems.

 

[Refueler]

I think the issue has more to do with lifespan than performance. It's suggested that carbs should be drained if left for three three weeks. Until ethanol, I could leave petrol in a mower all winter without problems.

That's where we will certainly differ ..... I have always had trouble starting garden engines / outboards if left with carbs full - long before Ethanol use.

Its not only me - for many years - its been suggested by many incl manufacturers / services to drain carbs if left standing ... because of - 2str : the oil mix .. 2str and 4str : the vaporisation of light ends.

Gasoline loses its 'potency' not because of Ethanol when poorly stored or left in carbs - it loses it because of the light ends vaporising off ...

The next effect is "gumming" .... this is the small blobs of brown you can find in bottom of containers / carb bowls etc.