Are all 2 stroke outboards unreliable or is it just mine?

[Paramotorgreg]

I inherited a Mariner 3.2 2-stroke engine when I bought my boat. At first I was very pleased, because I know that the power to weight ratio of 2-strokes is better than for 4-strokes and I understand that it’s not possible to buy 2-strokes in many places any more. However 3 years down the line I am in despair.... I had the motor professionally serviced and it still fails with boring regularity. I must have taken it to engineers at least 6 times to have the carburettor cleaned, the fuel tank flushed, and just to have it fixed when it refuses to start. We spend a lot of time on anchor so we need a reliable motor, many times it’s a long way for me to row the dinghy and way too far for my wife - especially in poor weather. I am thinking of throwing it away and replacing it with a 4-stroke.....are they any better?

[jamhass]

One of the biggest issues is gas with ethanol. Outboards, especially older 2-strokes hate the stuff. I know folks who swear by special (and godly expensive) chain-saw gas for that reason. At a minimum, use premium gas and avoid ethanol if possible, and don't leave ethanol in the "on engine" tank for long periods of time.

[Cheechako]

Farm supply stores with gas pumps often have real gas. Union 76 stations in some states sell it. Maybe google "ethanol free gas" for your area.
Back to outboards, it's just hard to say. Usually older stuff works pretty well. My little Merc 4 HP would start after sitting all winter on the 2nd or 3rd pull every spring.
But today's 2 stroke stuff like weed whackers or chain saws are absolutely terrible. I have 2: a Stihl one year old and a Ryobi. Both worked a few times and cannot be relied upon. The Stihl was used twice last year with real gas, drained for winter. This spring it will do nothing but start but not rev up. I sold it for parts on craig's list, looked new.They make them so you have limited fuel adjustment now. I bought electric and gave up on modern 2 stroke anything.

[a64pilot]

Your problems likely haven’t much to do with it being either four or two stroke, but the fuel system, which is common for both.

Only cure I know if is fuel injection, but that’s only on much bigger motors.

I think your best served by carrying a bucket of carburetor cleaner or a small ultrasonic cleaner and learning how to do the job yourself, as well as maybe a spare carb.

Use of fuel stabilizer really seems to help as well as draining the carburetor or running it dry if it’s to sit for more than a day or two.

[44'cruisingcat]

The problem with very small outboards is that the carburetor jets are so tiny they're very easily blocked.

Bigger 2 stroke outboards, say 6hp and up are generally reliable. Our Tohatsu 18 was pretty bulletproof for 8 years until a high speed collision with a submerged log. Then the engine still ran fine, but the gearbox got rattly.

[Don C L]

personally I wouldn't waste any more time or money on that one. Mariners had a bad rep in my neighborhood back in the day. If you can find an old Yamaha or whatever, even Evinrude, 2-stroke in good shape you should be fine. I have a 30 year old Evinrude 8hp 2 stoke that still runs fine and is reliable (with regular maintenance.)

[redsky49]

For the six times you previously had engine serviced, what was the issue, and how did they correct it?

[redsky49]

Originally Posted by Don C L

personally I wouldn't waste any more time or money on that one. Mariners had a bad rep in my neighborhood back in the day. If you can find an old Yamaha or whatever, even Evinrude, 2-stroke in good shape you should be fine. I have a 30 year old Evinrude 8hp 2 stoke that still runs fine and is reliable (with regular maintenance.)

Yep. My 24 year old Evinrude 6hp still reliable.

[sparrowhawk1]

Originally Posted by 44'cruisingcat

The problem with very small outboards is that the carburetor jets are so tiny they're very easily blocked.

Bigger 2 stroke outboards, say 6hp and up are generally reliable. Our Tohatsu 18 was pretty bulletproof for 8 years until a high speed collision with a submerged log. Then the engine still ran fine, but the gearbox got rattly.

Beat me to it. over the years even using filters and buying gas that was guaranteed not to have alcohol in it, always constant cleaning of carburetors of anything less than 5 horsepower 6 is better. Three months ago I purchased a 2.5 horsepower propane fueled outboard so far so good. Getting refills is a little bit more of a hassle but well worth it.
As a side note and I'm not recommending this but I know of a sailor that had a paint bucket full of carb cleaner and he would regularly take his carburetor off put it in the bucket overnight and swore by it.

[Davy J]

I am thinking of throwing it away and replacing it with a 4-stroke.....are they any better?

Modern 4-stroke motors are getting better/lighter every year. We have a ten year old Honda 2hp. It has been fairly reliable. I've only needed to clean the carb about four times in ten years, it's pretty easy to do, no need to take it to a dealer. It has a drain screw on the carb bowl, if not going to be used for a couple of weeks or more, it gets drained.

At the time I bought it, it was the lightest, smallest 4-stroke out there. Now Yamaha and Suzuki have offerings that may be even better. The Honda is air-cooled, which means I don't need to flush the motor. However, the trade off is that it is loud.

If I were in the market now, I'd have to consider the electric and propane models as well.

[mikedefieslife]

Everyone's been jumping on the fuel bandwagon. No-one has mentioned compression. Who knows how the engine was treated before the OP got it. It could have been run without 2t oil, there could be scoring to the cylinder etc.. a compression test would help check that.

The good thing is a top end rebuild, re-boring, and a new oversized piston is very easy to do. I've done it a few times on 2t motorcycles.

[sparrowhawk1]

Originally Posted by mikedefieslife

Everyone's been jumping on the fuel bandwagon. No-one has mentioned compression. Who knows how the engine was treated before the OP got it. It could have been run without 2t oil, there could be scoring to the cylinder etc.. a compression test would help check that.

The good thing is a top end rebuild, re-boring, and a new oversized piston is very easy to do. I've done it a few times on 2t motorcycles.

By his description it's not compression because if it was it wouldn't run good and then fail and then run good after service and fail, unless I'm missing something.

[Triumphant]

I have a 10 year old Yamaha 4HP 2 stroke. I use the motor every day. The quality of the fuel in my area is very bad, I used to have to work on the carb every 6 - 8 weeks then I started filtering the fuel into the tank when I was filling it up and the carb work went to about once every few years. I have also found changing the jets every few years helps.

[Time2Go]

My 4hp Evinrude ran like crap and was hard to start
So had the carb rebuilt and the engine ran fine for a bit.
Then back to the same old problems and almost impossible
to start. A friend suggested I look at the in line fuel filter.
Completely fouled, What the heck??
I had been running 15 bucks a gallon pre-mix no ethanol.
After much mucking about
It seems that tilting the motor to get the prop out of the water
stirred up the small amount of sludge in the bottom of the tank.
Knocked enough lose to foul the filter.
Cleaned up the tank, installed a much bigger in line filter
and haven’t tilted the motor
And no problems so far.
If your moving the engine about a lot
and tilting this could be your issue.
Cheers
Neil

[Compass790]

year 2000 approx Yamaha 2hp 2 stroke is totally reliable. But I always filter fuel as other posters suggest. Tiny jets don't take much to clog. Keep meaning to fit inline fuel filter as well.