Mariner 9.9 - New 10hp outboard choice.

[Fenlander]

Then it dawned what had happened. On my first trip at sea this Mariner had produced a very specific version of the Aerotec transom splash in that it hadn't come over the transom but caused huge amounts of water to be thrown up the leg and over the top of the engine... with such force salt deposits were over the engine inside the cowl having been forced up through the small drain holes.

Seawater must have been forced up this pipe into the top of the carb on this first run giving just a small amount of trouble but once it sat for a month between outings the salt dried out to a deposit that blocked the jets.

I have of course sorted the splash with the transom mod but also have re-routed this carb pipe keeping it in the driest place under the hood as shown.

[breezeblock]

don't worry about your warranty if it was fuel contamination it wouldn't be covered anyway

[Bigplumbs]

Glad you found the issue. I am sure that was very frustrating and indeed depressing on a brand new engine

[Fenlander]

>>> very frustrating and indeed depressing on a brand new engine

Yes very much so... although I'm a calm guy I drove home with the irrational thought of dumping it back to the dealer and buying something else.

But so pleased to find a logical reason not the engine's fault** so I've regained my trust.

**Well I do wonder at the routing of the breather pipe outside the hood with the potential for extreme circumstances to give this problem.

I'm a bit OCD and just in case similar ever happens I've already ordered a new 1/4" T-bar and 6" extension to put in the tool kit which together with a 10mm socket is needed to remove the carb. Also going to pop back to the dealer and order new jets as spares... far easier to swap them at the coast than faff cleaning them out.

[Bigplumbs]

Originally Posted by Fenlander

>>> very frustrating and indeed depressing on a brand new engine

Yes very much so... although I'm a calm guy I drove home with the irrational thought of dumping it back to the dealer and buying something else.

But so pleased to find a logical reason not the engine's fault** so I've regained my trust.

**Well I do wonder at the routing of the breather pipe outside the hood with the potential for extreme circumstances to give this problem.

I'm a bit OCD and just in case similar ever happens I've already ordered a new 1/4" T-bar and 6" extension to put in the tool kit which together with a 10mm socket is needed to remove the carb. Also going to pop back to the dealer and order new jets as spares... far easier to swap them at the coast than faff cleaning them out.

Looks like you have got it sorted and have a very good plan moving forward

[Last Tango]

Originally Posted by Fenlander

>>>

**Well I do wonder at the routing of the breather pipe outside the hood with the potential for extreme circumstances to give this problem.

It is a breather and not an overflow pipe...you wouldn't want that to spill inside the cowl ?

[Fenlander]

LT not sure I understand the thrust of your comment. Are you saying it's just a breather so what I've done re-routing is OK or would you have done different?

[Last Tango]

Originally Posted by Fenlander

LT not sure I understand the thrust of your comment. Are you saying it's just a breather so what I've done re-routing is OK or would you have done different?

Sorry ...open to misinterpretation. It was a question, just ensuring you're confident it is just a breather and not the overflow for the carb.

[Fenlander]

Ahh OK. No just the breather to enable the carb to work on the principle of... greater atmospheric pressure on the fuel in the float chamber than the lowered pressure in the carb throat venturi.

I've read up on this a bit and it's a real issue for competition dirt bikers to find an ideal position to terminate this pipe due to wet and mud etc.

The only time it could act as a drain/overflow would be when laying down in the car if you didn't run it dry before travelling where it's just possible fuel could run through the carb passages and out of the pipe.

I guess Mariner never expected a constant upward flow of water or spray at that height on the leg where the pipe terminated... obviously never tested an Aerotec on form!