Outboard problems, Honda 10hp

[bellamia]

Hi all
Having a few problems with my out board a Honda 10hp 4 stroke. I have changed the impellor but still have only got a medium sort of spray of water from the pee hole, should this be a steady flow? I have a feeling it may be scaled up inside, if so whats the best way to clear this out as there apears to be no flushing holes, i have some kettle descaler ready & hope this will do the job. Also the engine is hard to start and cuts out after a few minutes of running, i have removed and cleaned carb but no better, any advice greatly received thanks. Engine is being run in a barrel with fuel tank on the floor

 

[AngusMcDoon]

The water tell-tale jet often becomes blocked with a piece of something. Try giving it a poke with some wire. If that does not clear it, take off the pipe that leads to it and make sure that is clear, muck can get caught in there too. If still no luck, take off and check all the rubber cooling pipes that move water around the engine. These are easy to remove and check, but do them one at a time to make sure you get them back in the right places. This is all easier to do before trying descaling or dismantling.

Next problem - hard to start. Are you hand-starting or using an electric start? If hand starting, there's a bit of a technique to these as a fair old pull is required to start a twin cylinder 10hp 4-stroke. You need to pull the start rope slowly until you feel resistance, then let the rope back in, then give it a good yank.

If this does not solve it, then it's all the usual checks, spark plugs + caps, high-tension cables, clean fuel, choke/throttle mechanism working.

As for cutting out, this sounds like a fuel supply problem. Is the fuel tank too low and giving the fuel pump a hard time? Try raising it to a similar level to the engine. Outboards are not usually installed a long way above their fuel supply, and the lift pumps are not huge. If this does not help, what about the fuel filter, is it blocked? Or are there any air leaks in the pipes/connectors? It may also be that the lift pump is getting old and needs a service. You can replace the pump completely, but that's expensive. If you're good with fiddly bits, you may be able to buy just the seals and diaphragms, and replace those. On Yamaha's you can just turn 'em over when they wear, but I don't know if you can do that trick with Hondas.

Finally it may be a carb problem. A quick bit of cleaning you can do is squirt through some carb cleaner when it is running, and be persistent. Lots of small goes. If that doesn't fix the carb, then it may need dismantling, but that always scares me!

 

[bellamia]

Thanks for advice the teltale is clear i've already poked around in there, i have an idea the engine isn't getting enough flow of water around it as it apears to be getting hot, so will try removing the cooling pipes as you advise. Engine is a pull start & am making sure its on compresion stroke before giving it a good yank, has got a spark but doesn't look very bright not sure as used to messing with cars? will also try lifting fuel tank & strip down lift pump & check diaphram etc

 

[Gordonmc]

Is there a thread on the water outlet (pee-hole).
If so you may be able to fit an adaptor to take a hose for reverse flushing.

 

[bellamia]

No there is no thread in the pee hole, there are 2 of them about 3.5mm dia, does all the water leaving the engine exit through these 2 holes?

 

[tedbarnes]

I think you will find that the second "pee hole" is nothing to do water, but is a fuel drain to allow you to empty the carburetter. Unfortunately I can't remember which is which.

 

[dickh]

Try a new set of plugs - I only have the 2HP but after difficult starting, I checked the plug and the insulator cone had broken off an slid down the centre electrode. A new plug fixed the problem, by the way, always ask for the NGK plug by number, don't ask for a Honda plug - saved me about 75p! Identical apart from the box.

 

[bruce]

in the water pump, if the plate that the impeller rests on is scratched/worn with grooves or the area the blades rub against is scored, you may have to replace the plate and housing. if the impeller is old and/or blades are bent, it may need to be replaced also. the water outlet hose comes from the plate that has the intake attached/molded to it, and held on with about 6 bolts. ad some carb cleaner to the gas just like a car, and run it. good luck, am working on my honda 100, 10 hp at this time.

 

[gary_yank]

On mine I had to replace the thermostat and clean out the housing. If the motor has not been used in a long time then there may be a scale build up in the housing, mine had a lump of the loose stuff that formed after the motor reached operating temperature.
Check the venting on the fuel tank. My old tank vent had clogged up and would allow the motor to run about ten minutes and then it would shut off due to the vacuum built up in the tank.
I do not know if the petrol over there is the same as here but ours gets stale rapidly and I use a fuel stabilizer.