Honda 15 Petrol Outboard - Stalling when moving from forward to neutral

[Megafugle]

Hi,

 

Am hoping someone could help me/point me in the right direction. We have a Honda 15A BAAS 1203567 petrol outboard engine attached to a Dawncraft 25 boat which we use on the Grand Union canal.

 

The engine has been recently serviced and passed with no problems. Carburettors are fine, thermostat is fine, oil levels are fine and under test conditions everything checked out ok.

 

However, when we use the boat, when coming into land, or to turn around, we are having issues with the engine stalling. This seems to happen when we are moving from forward throttle into neutral, particularly when doing this at low speeds. The engine always starts up again immediately, and moving forward or backward when cruising at a constant speed is fine.

 

Does anyone have any idea why when we move from forward to neutral we are experiencing this stalling? We have had the engine turned up so that it idles at high revs but this does not seem to have helped. Weve replaced the fuel with brand new fuel and this also doesn’t seem to have helped.

 

Any ideas most welcome. My favourite toy is currently sat outside not moving and I miss it!

 

Thanks.

 

[Tony Brooks]

I would suspect the idle mixture has been set up incorrectly during the service - that is if the Honda has an idle mixture screw. Or maybe the idle speed was set a bit low.

 

If it has an idle mixture screw (not idle throttle stop) then get the engine nice and hot and carefully note the position of the idle screw. Then little by little move it one way and then the other. If the revs fall go the other way. When it is running a s fast a It will I would unscrew the screw about1/4 turn so there is no chance of it running too weak and the set the idle speed to the manufacturers spec. by means of the throttle stop.

[Megafugle]

Hi Tony,

 

Thanks for your email. We had the idle speed tuned by RCR and when sitting in neutral at rest, the engine ticks over fine. It only seems to encounter difficulty when we have been underway for a short while and then come to a stop. Could this still be linked to the mixture?

 

Thanks,

[Tony Brooks]

1 hour ago, Megafugle said:

Hi Tony,

 

Thanks for your email. We had the idle speed tuned by RCR and when sitting in neutral at rest, the engine ticks over fine. It only seems to encounter difficulty when we have been underway for a short while and then come to a stop. Could this still be linked to the mixture?

 

Thanks,

That is what I said but I have no knowledge of the outboard and have never worked on one.

 

It could be lack of cooling water allowing partial engine seizure but I very much doubt it. Why it may lack cooling water flow is open to question but a worn water pump impeller (if it was not checked during the service) or furred up internal waterways may be the answer.

 

I assumed that you are familiar with the boats so discounted leaving the fuel tank vent screw closed.

 

Incorrect spark plugs fitted during the service having the wrong heat range is another very long shot.

 

I doubt it has contacts like the old outboards so there is always the possibility the electronic ignition modulo is breaking down       when hot and there by producing weak sparks.

 

Some Honda outboards had problems with getting a good negative connection between the ignition modulo and the engine block. Make sure its tight.

[Neil2]

Check the float chamber - for some reason these motors have a tendency to collect "grit" in the float chamber which can cause the intermittent fault you describe.

[Megafugle]

Thanks for all the suggestions, will try this out at the weekend and see how it goes.

[Mad Harold]

I agree with Tony Brooks. It sounds like too weak a mixture.

Once had a problem with a Yamaha outboard stalling when engaging fwd.All the advice from several people was to increase tickover speed which I had already done,but it engaged fwd with a "thud" and stalled.

The cure was to set the tickover to the book figure (900rpm if I remember correctly) it then engaged fwd smoothly without stalling.