Additives for small outboard petrol. Any recommendations?

[Flica]

For those who advocate using premium petrol to avoid FAME, I asked the petrol; companies , and only BP said that their premium petrol was FAME free.

Not surprising, probably felt they had to humour you. Fatty acid methyl esters are only added to diesel fuels, commonly known as bio-fuels they are acknowledged to gum up more than inorganic diesel and to be hygroscopic.
In some countries a minimum level of ethanol is legally demanded - this also is hygroscopic and forms long chain polymers when stored.

 

[chewi]

Not surprising, probably felt they had to humour you. Fatty acid methyl esters are only added to diesel fuels, commonly known as bio-fuels they are acknowledged to gum up more than inorganic diesel and to be hygroscopic.
In some countries a minimum level of ethanol is legally demanded - this also is hygroscopic and forms long chain polymers when stored.

my mistake, it was ethanol I was asking them about. I am no chemist.

 

[steve66]

Chewi... long time no speak. Did you ever get that honda finished??

 

[chewi]

its working as spare, but the exhaust pipe is a colander, and it smokes.

I reluctantly got another one for daily use.At least its the devil I know. The other 4 strokes are much heavier and have waterpump issues, (I am often in very shallow water.) the older 2 strokes have oil mix issues.
Why oh why did Honda not fix the issues whwn they facelifted it? It's still git lots of mild steel fixings.

 

[steve66]

its working as spare, but the exhaust pipe is a colander, and it smokes.

I reluctantly got another one for daily use.At least its the devil I know. The other 4 strokes are much heavier and have waterpump issues, (I am often in very shallow water.) the older 2 strokes have oil mix issues.
Why oh why did Honda not fix the issues whwn they facelifted it? It's still git lots of mild steel fixings.

Ha ha dont worry about the exhaust its designed to have holes in it to drain the water if its inverted. They do smoke if they are slightly overfilled.
Honda only designed them to last no more than 10 years

 

[chewi]

Unsurprisingly it doesn't say 10yrs on the adverts....!

 

[bitbaltic]

Ha ha dont worry about the exhaust its designed to have holes in it to drain the water if its inverted. They do smoke if they are slightly overfilled.
Honda only designed them to last no more than 10 years

Haha the 20 year old one I bought from you is still going strong Steve!

Used it this afternoon for the first time this season, started fine after running it dry at the end of last season and draining the tank, ran it dry again to ensure it starts perfectly next time- thank you for the advice to do that.

 

[steve66]

Haha the 20 year old one I bought from you is still going strong Steve!

Used it this afternoon for the first time this season, started fine after running it dry at the end of last season and draining the tank, ran it dry again to ensure it starts perfectly next time- thank you for the advice to do that.

Ahhh see thats the difference. Honda built them to last 10 years, I build them to last another 25 on top of that . Ha ha
Great to hear shes behaving. Any issues give me a shout!

 

[lw395]

"Drain the carb" is not an operation requiring anything more than turning off the fuel tap and letting the engine run on until it stops. Simples.

That is not draining the carb.
Draining the carb is undoing the drainscrew in the float bowl and letting the fuel/water drain out.

 

[lw395]

For the third time in less than 2 years my Suzuki 2.5 has suffered a blocked jet due to the formation of little balls of fuel and water emulsion - a sticky, jelly-like material. ....?

Cleaning the carb less than a couple of times a year is no big deal.
Water in outboard carbs, like motorbike carbs, has been an issue long before bio-petrol.
Sticky gunge in the carb is more likely when the engine is not used very much.
Every practical boat owner should know how to take off the float bowl and do at least a basic carb clean.
Bowl off, clean inside of bowl, squirt innards of carb with aerosol carb cleaner will usually do the job in 3 minutes.
A proper job of stripping the carb and cleaning each part might be needed in severe cases.

 

[andrewbarker]

Sorry I couldnt be of any more assistance to you Andy. I have very little knowledge with small outboards carbs and fuel but I thought I would offer the very limited knowledge I have.

Honestly Steve, you don't seem to know anything. The OP's outboard has only blocked 3 times in 2 years. On the other hand, I followed your advice on the one you serviced for me and it's blocked .............err never in 5 years.

 

[steve66]

Thanks Andrew. The advise I givd out is advise I have gained through practical experience over many years. None of it is hearsay or what I have read. I have experienced all issues quoted in this thread and have found ways of solving them.Im not saying you should follow what I say or do and everyone else is wrong. I genuinely cannot comment on how good fuel stabiliser is as I never have had the need to use it. My carbs dont get gummed up.

 

[lw395]

For those who advocate using premium petrol to avoid FAME, I asked the petrol; companies , and only BP said that their premium petrol was FAME free.

I think that BP premium petrol seems to get my fuel injection motorbike running sweetly if it hasn't been used for a month or so. I also use a drop of whatever injector cleaner I have to hand if any. It's hard to be definitive as we are talking about slightly smoother idle and a few more tanks of 'normal' probably do the same.

 

[lw395]

Honestly Steve, you don't seem to know anything. The OP's outboard has only blocked 3 times in 2 years. On the other hand, I followed your advice on the one you serviced for me and it's blocked .............err never in 5 years.

I think a lot depends on how a small engine is used, and where it's stored.
I used to keep an outboard in a damp shed. Water in the carb was relatively frequent. I believe the dregs of petrol in the carb evaporate, cooling the carb, then dew forms in the carb. Some of that ends up in the float bowl.
If you use an outboard a lot, it will swallow the smaller droplets of water that have formed over a few days. But more modern outboards seem to have smaller jets.
Petrol with ethanol in it will dissolve some water and take it into the engine. Provided the petrol is not already saturated. So regular long runs using a decent amount of fuel will help.
It's good to keep your fuel in a properly sealed container between the fuel station and the engine.
Empty the tank and cans completely from time to time and remove any drops of water.

Old fuel can be a nuisance, that has not changed since the 60s. I have a manual for a 70s italian motorbike which advises that fuel stored more than a few months 'may go sour'.

 

[andygc]

Sorry I couldnt be of any more assistance to you Andy. I have very little knowledge with small outboards carbs and fuel but I thought I would offer the very limited knowledge I have.

I've come back to this thread simply because of the advice various people have given about running the engine with the fuel tap off until it stops in order to empty the bowl. My frustration at being told things I didn't need to know was not intended to be rude, so I apologise.

I've just cleaned up the engine at the end of the season and I have run the engine until it stops. I've taken the carburettor off to check it over. The residual fuel in the bowl of my engine's carburettor when it will no longer run is approximately 20ml. The only way of emptying the bowl after use would be to open the drain screw. That is not a practical solution to avoiding corrosion when the engine is being used during the season.

 

[fredrussell]

Torqeedo should put a link to this thread on their website.

For what it’s worth I use fuel stabiliser and don’t drain the carb. I’m just not prepared to mess around with a tiny screw and a gelcoat removing volatile liquid on a boat rocking around on the big briny.

 

[Ludd]

I grew up with 10:1 Seagulls, always ran carb dry. Never a problem.
For the last 9 years I' be had a Malta.,100:1. If it doesn't start FIRST pull, I strip and cleancarb, takes half an hour.
No big deal. It is in use year round--- my dinghy is my car.

 

[gregcope]

So when we're away from home we anchor, go ashore for a meal, come back, drain the carb, go to bed, wake up, refuel, go to the beach, drain the carb, swim and sunbathe, have a barbecue, refuel, go back to the boat, drain the carb ........
Thank you for a really helpful suggestion. That's much appreciated.

It only takes a few minutes, if that, runing the engine with the feul closed off to achieve this.

 

[thinwater]

Thank you thinwater and sarabande.

I do close the vent, and I've a waterproof cover for the motor when it is on an outdoor rack ashore. The owner's manual for the Suzuki 2.5 does not recommend running the carburettor dry when stopping the engine (I rechecked), and I don't do it.

That makes sense. I was told it was bio-ethanol+water emulsifying that created the problem, but presumably the corrosion follows on from that. There's certainly evidence of corrosion in the bowl. I can't help but think that bio-ethanol is at the bottom of the problem as I never had any trouble with blocked jets before it started to be added to petrol.
And that also makes sense.


sarabande, I would certainly be grateful to know if there are any potential problems with BioBor.

Biobor EB is the one you want, not Biobor. Same company, totally different product.

 

[thinwater]

Originally Posted by andygc

"So when we're away from home we anchor, go ashore for a meal, come back, drain the carb, go to bed, wake up, refuel, go to the beach, drain the carb, swim and sunbathe, have a barbecue, refuel, go back to the boat, drain the carb ........
Thank you for a really helpful suggestion. That's much appreciated."

So funny! Or course you don't need to. Like anchor threads, small outboard maintenance is a religion, and people are quick to comment on stuff they have not researched or actually tried.

Many of the outboard manufactures have removed daily "run empty" recommendations from the manual. It turns out that all that does is increase the odds that the little that remains will dry out ad turn into gum. Gas just does not evaporate that fast in a small, semi-sealed space. Just try this with a small glass bottle and a hole the size of the bowl air vent (2mm); it will take months to dry even 10%. The dry bowl thing is myth for engines stored less than a year.

As for corrosion, use a good additive (Biorbor EB, Merc store and start, Star tron, and not Stabil), close the tank vent when not running, and you won't have problems. Much easier. You should go many, many years between carb cleanings. I have since I started using Biobor EB. (I'm a lab and magazine product tester, not an industry vendor.)