Outboard Problem

[Old Thady]

My 16 foot daysailer has a 2.5HP, four stroke Suzuki outboard. It came with the boat so I don't have the original manual.
The engine stays on the boat (on a swinging mooring). It has never given trouble until now.

A while ago, I went out to the boat and found the outboard fuel cap open. I assumed I'd forgotten to replace it the last time I was aboard when I topped up the fuel before taking the can ashore. Foolishly, I didn't check the level of the tank.

The engine started but cut out after a few minutes use. The tank was empty. I realised that the problem wasn't my forgetfulness. Someone must have come aboard, taken the fuel and left without putting the cap back. Luckily, I was able to sail back to the mooring.

A few weeks passed during which I didn't use the boat due to a minor medical issue. Today, I went out and filled the engine with petrol but the engine will not come close to starting. It's as if the kill cord were off.
I suspect the fuel became contaminated or degraded while the cap was off (rainwater?). Perhaps I caused a clog by running the engine dry.

Are there some simple steps I can take to try and clear the fuel system before putting in fresh petrol? I'd rather not bring the outboard ashore but maybe that's the practical thing to do.

 

[Snowgoose-1]

Looks like a complete Carb clean is required . Also flush the fuel pipes

 

[snowbird30ds]

There's a drain screw on the bottom of the carb, open till good smelling fuel comes out and try again after cleaning the plug, you may get away with it.
There's a hole in the lower cover not quite lined up with the drain spigot so a short bit of hose saves all the crud in the cover.
If it don't work the carb will need a proper clean and if water has got into the engine the exhaust valve is prone to sticking open and the pushrod drops into the sump.

 

[Boathook]

I would prefer to take that size engine home and sort out. 2.5hp is the size a lot of people take back and forwards all the time.

 

[thinwater]

Also replace the fuel filter, if applicable. If there is not a fuel filter, you would be very wise to add an in-line gasoline mower filter in the hose. This can solve a lot of problems.

Additionally, if you got water in the carb (you did) you may have corrosion and some blocked up jets, requiring an internal cleaning of the carb. The cap and the vent should be closed anytime the motor is not running. Even humidity from the air is a risk.

A 2.5 hp motor is nothing. Take it home and sort it out. Run it in a waste bin (cleaned) filled with water.

 

[Old Thady]

Thanks for your advice Snowbird, Snowgoose, Boathook and Thinwater.
I think I'll bring the outboard home and try to do a thorough job.

 

[PetiteFleur]

And also use Premium E5 petrol with Honda fuel additive. I've got an epropulsion elite electric outboard so haven't used my Honda 2.3 all this year. Today I thought I would start the Honda - fuel on, choke out, air bleed screw loosened, set the throttle and it started first pull!
Use E5 as it doesn't deteriorate like E10 petrol. The extra cost is infinitesimal.

 

[winch2]

Second what he said about the fuel. Never ever put E10 in. Use E5 plus, an additive for 100% reliable starting/running.

 

[Old Thady]

Thanks Petite Fleur and Winch2 for those pointers about the fuel.

 

[Stemar]

You can see the manuals here. Not sure if you can download them, though