Keeping small outbords functioning

[larsake]

I have a Yamaha 2.5 hp four-stroke from 2018. I have had a lot of problems with during the years. Sometimes it doesn't start at all, sometimes it works poorly just with the choke out some. I have had it at Yamaha service many times and after a service (cleaning of carburettor) it will work for a while. A technician here in Spain said one has to let these small four-stroke motors go at least a couple of times each month to make them functioning properly. That is impossible when you leave your boat for long periods now and than. Is there anybody having an advice to avoid this problems?

[CaptTom]

Just from the thread title I was going to suggest carburetor issues. You confirmed that's been the problem before.

I'm not sure what the fuel situation is in Spain, but here in the US they sell a gasoline/ethanol mix which doesn't keep very long. Even before that, leaving a small engine unused would cause problems if you stored it with fuel in the carburetor. Small engine carburetors are easy to plug up with debris, "gunk" and dried-up fuel.

One fix is to run it dry before storing. Around here they also sell what they call "engineered fuel" in cans in the home improvement and small engine stores. Running the engine on that before storing has worked well for my dinghy outboard. There are also additives you can buy which claim to help, and others which claim to clean the carburetor, but it's hard to know which really work and everyone you ask has different opinions.

[larsake]

Originally Posted by CaptTom

Just from the thread title I was going to suggest carburetor issues. You confirmed that's been the problem before.

I'm not sure what the fuel situation is in Spain, but here in the US they sell a gasoline/ethanol mix which doesn't keep very long. Even before that, leaving a small engine unused would cause problems if you stored it with fuel in the carburetor. Small engine carburetors are easy to plug up with debris, "gunk" and dried-up fuel.

One fix is to run it dry before storing. Around here they also sell what they call "engineered fuel" in cans in the home improvement and small engine stores. Running the engine on that before storing has worked well for my dinghy outboard. There are also additives you can buy which claim to help, and others which claim to clean the carburetor, but it's hard to know which really work and everyone you ask has different opinions.

Yes I think you have a point there! I mean drive the carburettor empty. We use that engineered petrol (Aspen) all the time and i have thought that should help, but apparently not. I have also used some additives without sseeing any difference. Next time I leave the boat I will run the engine dry.

[chris95040]

For lawnmowers, over the years I've migrated away from "running it dry" to "topping it off with stabilized fuel."

I think its hard to really eliminate all the fluid from a system so you end up with a coffee stain of gummy varnish somewhere in there.

I keep my outboard in the basement though, so that one still gets run dry so it doesn't smell so much. I do switch to stabilized gas in the fall though- so whatever gets left behind is still "stabilized".

Not to say I have any idea if any of this voodoo works. I do find I haven't touched a lawnmower carburetor in probably a decade, but that could just be because I buy better lawnmowers now?

If you let a sample of unstabilized gas evaporate slowly in a poorly sealed container, I'm fairly certain you get left with a gummy residue. Surely you _still_ do even with stabilized gas, no?

[larsake]

By ”stabilized” fuel I take it you mean ”alkylate” (=Aspen), or??

[noelex 77]

I added a larger fuel filter to our Yamaha 2.5, and this seems to have helped with the frequency of carburettor blocking problems.

[rslifkin]

Originally Posted by chris95040

For lawnmowers, over the years I've migrated away from "running it dry" to "topping it off with stabilized fuel."

I think its hard to really eliminate all the fluid from a system so you end up with a coffee stain of gummy varnish somewhere in there.

I keep my outboard in the basement though, so that one still gets run dry so it doesn't smell so much. I do switch to stabilized gas in the fall though- so whatever gets left behind is still "stabilized".

Not to say I have any idea if any of this voodoo works. I do find I haven't touched a lawnmower carburetor in probably a decade, but that could just be because I buy better lawnmowers now?

If you let a sample of unstabilized gas evaporate slowly in a poorly sealed container, I'm fairly certain you get left with a gummy residue. Surely you _still_ do even with stabilized gas, no?

I'll second this. Any gas I buy for any small engine (or anything that might not have its fuel used up quickly) gets the blue marine Stabil added right when I buy the gas. And I never run anything dry, just fill the tank before off-season storage. For long storage periods I usually fog the engine as well, figuring an oily carb is less likely to gum up. In general, I've had very good luck with things staying working.

For the dinghy outboard I spliced a big spin on fuel filter into the line from the external tank. It's a finer filter than the internal one on the outboard and also a water separator, so it should keep the carb cleaner and happier.

I tend to stick to ethanol free gas when possible for the dinghy outboard and lawnmower due to moisture concerns in the dinghy environment and the lawnmower being jetted so lean that it runs noticeably better on the ethanol free stuff. But for everything else I own, it gets whatever is available, usually the ethanol stuff.

[Jammer]

I have a Suzuki 2.5 DF and also an older Johnson 3hp two cycle and a Honda 9.9 which is carbureted. I do all my own repairs.

Generally there is no magic solution on these; you want to use fresh, clean, dry fuel and a corrosion inhibitor. If you can get ethanol-free fuel then use it. I use Stabil Marine 360, studies have shown it helps reduce corrosion.

The etiology of these carb failures is typically that metal (mainly aluminum) portions of the fuel system corrode internally due to water and salt suspended/dissolved in the fuel, forming corrosion particles that break off and then clog needle valves, passages, and jets. Filtration doesn't necessarily help because the particulate material is formed downstream of the filter.

Studies have shown that running the carb dry between uses does not improve overall engine reliability.

Despite best practices I find that I have to disassemble and clean carbs from time to time (every few years).

Some cruisers carry a second carburetor for their dinghy motor and swap it in when the old one fails, then possibly rebuild the old one when it is convenient to do so.

A fact to consider is that, as of today, aftermarket carburetors for the Yamaha 2.5 are for sale on walmart.com for $30 and on AliExpress for under $15. Typically these aren't really rebuildable but since the purchase price is less than the parts costs for a rebuild it doesn't matter much.

For context, OEM carbs are around $150 and the overhaul kits are around $30. If a carb is rebuilt often it usually isn't necessary to use an overhaul kit every time.

I like oars more and more as time goes on.

[MicHughV]

Those little engines by their very nature have very little carbs.
I've taken many of these apart before.
Somewhere on the carb body you'll find a mesh screen filter barely larger than a match head. If it's clogged up, which it probably will be, it will be near impossible to find as it will look just any other part of the carb boy. If you do find it, flush it out with a carb cleaner nozzle ( you can get these at any auto store) taking care to not over do it.

Alternately, just replace the entire carb. Just go to Amazon and type in the engine size and any other identification number you can find. These are typically very inexpensive.

Here, I did it for you. Not sure if this is the correct one. If not, go to Amazon and find one the looks similar.

Areyourshop Carburetor Carb for Yamaha 4 Stroke 2.5HP 2HP F2.5A Outboard Engine 69M-14301-21 69M-14301-20 69M-14301-00

[Cpt Mark]

Engineered fuel. $44 at home depot for 2 gallons. Yikes! We have a few service stations that sell ethanol free gas. $6 a gallon. All I run in my engines. Engineered fuel is simply ethanol free fuel

[Chotu]

Honestly, the only solution to this problem is to buy outboards that don’t have carburetors. I know that doesn’t work for 2.5 HP. But it’s the sure fire way.

I bought a brand new Honda years back. Never ran right from the factory and no one could get it running right. Carb problems

now that I no longer have carburetors on board, I no longer have problems

[PaulSommers]

I have had so many problems with 4hp 4-cycle outboards that I am also going the carburetor-free route - a Torqueedo electric with a spare battery, and more solar panel/battery capacity to charge the Torqueedo batteries. Expensive - but so are the outboard mechanics. And now I don't have to carry gas on board, a definite plus. Anybody want a Suzuki 4hp 4-cycle outboard in the Sea of Cortez?

[chris95040]

I was just about to post that I don't seem to take any special care of my single-cylinder 4 stroke tohatsu 5hp outboard other than throwing "Sta-bil" in the tank as I get to the end of the season, I've had it for almost 15 years, it's in New England dangling off the dinghy from april through november, and I can't remember the last time I had a problem with it.

But then I realized what a stupid thing that would be, to taunt fate so recklessly.

(And in truth I know I *have* had that carb out and in my hand before - but I think that was the moment I decided to start trying Sta-bil.)

[Bowdrie]

Originally Posted by Jammer

I like oars more and more as time goes on.

That's the spirit, those which had British Seagulls learned early on not to worry about keeping them running.
It was much easier to perform maintenance on a pair of oars or up-grade them every so often.

[MicHughV]

Some people just have an evil spirit that descends onto their outboards.

I've owned numerous outboards, both 2 stroke and 4 stroke, of all sizes, and I can't remember a time when I've ever had a problem with them.

My secret....I talk to them and tell them to be mindful of what may happen to them if they decide to become misbehaved