Help, 35hp Outboard Overheated

Wee Dafty · 20 August 2012, 11:01

We have a 2 stroke Selva 35hp outboard. Yesterday we noticed a loss of power so turned off the engine. We noticed steam and then discovered that a plastic bag was wrapped around the water inlets. We got a tow back to the harbour and left the engine to cool down (about 1 hour or so). We restarted the engine and it idles fine, however, when we engage gear it cuts out. Can anyone offer some guidance.

Many thanks

9D280 · 20 August 2012, 13:15

At least it still turns!

In neutral, does the prop still turn?
Can you pull the spark plugs, disengage the anti start in gearlever & see if it spins OK in gear? I'm thinking if you got a bag over the prop, has something gotten wedged in the prop - gearbox space?

I don't know these engines, but also check out the throttle linkage is all still moving - you may find the extra heat has cooked some grease and something isn't following a cam the way it should. Most outboards the throttle moves the spark advance, and the throttle follows on a roller or sprung - damped lever

Alternative 2 - does it idle the way it used to? have you randomly got a blockage in a carb jet that would have happened anyway, overheat or not?

Locozodiac · 20 August 2012, 18:43

When an engine overheats severely smoking heavily due to plastic bags, banana peels blocking side water intakes you must torque back head gasket to specs, if doesn't better, replace for a new one, but before doing so, check head with a metal ruler to be completely straight and even border to border, as you already could have a warped head product of the overheat. When replacing new gasket won't achieve a perfect chamber seal between crankcase and head walls. Take advantage to clean all internal engine water passages.

It's always a must visually check at all times water peeing through small lateral hole located at right side of engine if boating in kelpie, contaminated seas. If you drive sitting opposite peeing hole, you will never see engine peeing and that's overheat candidate to ruin your boating day.

Happy Boating

Wee Dafty · 21 August 2012, 14:34

Thanks for that, I hope it's not that severe. After it cooled and I re-started the outflow from the tell-tale appeared to be as normal. I am aware that this engine has an overheat cut out that drops it back to a single cylinder but cuts out when you try to propell. I did not get a chance to properly cool it down and try it before I had to head for home, and have my fingers crossed that it will be okay. New impeller ordered as that will surely have suffered!! I will check to prop shaft for any obstructions also. Thanks

Locozodiac · 21 August 2012, 16:36

Usually warped head condition is product of having the impeller fried, that is melted inside water pump housing when boating at near full wot for long periods and you not being aware of debris obstruction at water intakes.

You can even melt plastic cables and fried thermostat along if happens to have plastic/rubber parts. Anyway re torque head gasket with torque wrench to specs as definitely will be bit loose.

Happy Boating