Suzuki DF15AS Service Scare

[DaveRolph]

This post is mostly for information for others but also a bit of a puzzle !

Its been a week since we took the OB in for its first service at Pennine Marine.

Half an hour after dropping it off we got a call to say we should come back as there was a problem.

We were shown the spark plug that was heavily coroded and the water that had come out of the bore and they wanted to check with a bore gague to check for corrosion.

Panic set in at this time, the engine had run less than 15 hours and had been run in to the manual specification and had been thoroughly flushed with clean water since its venture on the Sea, it had not misfired at any stage and was running perfectly on the last run.

Pennine marine later called to say the engine was running and there was no corrosion, we watched the engine running and all was well in the world again !

The puzzle is how the water got into the bore, it was flushed in an upright position and had not been layed flat since (other than to take for the service).

Our flush technique was questioned and if we had the engine runnning at the time (we had not), Peter suggested we should be running the engine while flushing (we had not seen this in the user manual!).

The other theory they had was that if when coming to shore a following wave pushed up the exhuast outlet and the only way the water could get in was up through an open exhaust valve (which is logical my father in law explains! but it sounded unlikely and certainly not on my watch !).

I guess that the lesson learned here is to always run the engine when cleaning (thinking about the safety first of course !).

I have to say that Pennine Marine went that extra mile to help us and take the time to explain things to us, I would highly recommend them.

If anyone would like to add further comments to this thread that would help us and fellow forum users that would be great.

[Cliff]

Glad there was no damage done Dave.. When I picked up my new tohatsu at the weekend, I was also told that the flushing should be done without the engine running. A hose attachment comes with it which screws into the connector port, maybe this is a refinement on new engines? because you can get a fair amount of water pressure through the sealed connector. The manual says that you can also flush in a tank with the prop removed. Be good to get other opinions as to the best method, and possible cause of the water ingress in yours.

[Si Crowe]

I've never flushed any engine without it running (2hp up to 225HP and everything in between) and always on muffs. the impeller is spinning properly and you can gauge the flow out of the tell tail properly. it's noisy but that's whats worked for me. the water pressure with a hose and muffs is negligible so no undue stress on seals.

[Steve]

Hi Dave

That's not good to experience that - glad all OK though. Not sure about why you had this water where it shouldn't be, so if you find out, be good to know! But with regards flushing, it's page 57, 58 and 59 in the manual:

new doc 2018-03-07 16.55.14.pdf

(1.42 MiB) Downloaded 85 times

The hose attachment that Suzuki supply is useful if you want to flush the motor while at a slipway with a hose, but you must not run the motor using this method.

Suzuki's recommendation is to use muffs, which you put over the water intakes near to the prop. Turn the hose on full and start the motor. If there's no water from the telltale jet, you need to shut off and investigate why. Running dry will burn out the impeller very quickly. This method does quickly flood your garden / drive though...

My preference is with the motor on it's stand, and a large trug (or barrel) underneath filled so that the water more than covers the cavitation plate. I run it in neutral for about 10 mins so the motor warms up a bit. I don't take the prop off, but am extremely careful not to run it in gear anywhere near my fingers / anything else.

I did try using the wheelie bin, which is about my waist high and very sturdy. You can clamp the OB on the side and fill it with loads of water. Trouble is, to lift the OB in, you need to lift it to shoulder height, which is blooming hard to do! And then you have about 80l of water to get rid of. Far too much effort for me!

Hope this helps?



Steve

[rogerblack]

My 4 HP Mercury had a brass adaptor for flushing, but my 15HP needs the muffs, which requires the prop to be removed; even then it's difficult to fit properly amd as Steve says p!sses water all over the place. At base, I use a rectangular plastic waste bin, which I can slide under the motor mounted on it's trolley, then fill with the hose. I used to faff about siphoning the water out with a short piece of hose when finished but then had the bright idea of fitting a cheap water butt tap from the local garden centre, so I can now drain it away safely.

I still used to have to remove the prop on the 15HP, as twisting the throttle to warm the engine up enough for the 'stat to kick in also engages forward or reverse gear, which would whizz the water out of the container. However a kind and wise chappie called The Gurnard showed me how to disengage the gear linkage under the cowl so this was no longer necessary.

[Mitch]

When I bought the mariner I was told not to use muffs as you need to see that the water pump is working ok, cover the intakes with water, start it up , do not put it into gear, & let it tick over until it warms up to normal operating temp & to make sure the water is coming out of the outlet ok.

[Martin]

I generally use a hose where possible at the site, quick none running flush through and then once home I lift my 20hp into the wheely bin and fill it up with water just over cav plate.
I then leave it running for about 20mins, gets it nice and warm and flushed clean. Disconnect the fuel line, (I clip on a spare free flow coupling) and allow the motor to run dry of fuel.

DAVE, have you flushed your outboard and tilted it too far whilst the leg had water in?
If you don’t drain it properly and the exhaust port happens to be open then the water will run up the leg and flow into one of the pots... bad news!

I’m an ex car/Hgv mechanic and I’ve spent some time talking to the mechanics at Pennine Marine, I too rate them highly and wouldn't hesitate recommending them.

Martin

[DaveRolph]

Thanks everyone for the input, Steve thanks for attaching the manual sections, I have re-read and all makes sense but still not sure how it happened.

Martin the engine was upright and stayed that way from cleaning with the hose and left in the position until it went for the service.

When I go away I was thinking of taking a bin like Rogerblack, leave the engine on the boat and tilt into the bucket (propeller of for safety) then flushing with hose at home.

The instructions do clearly provide details for flushing while not running in exactly the way I did it, the only difference is that I probably did it for a lot more than 5 minutes, surely you can't over clean it ?

[Martin]

Steve, quick tip for the wheely bin...
Tilt it down, pop the outboard in it, lift it back upright,then fill with water and flush the outboard.
When you’ve done flushing, plunge a hose into the bin agitate it up and down and the water will start to syphon out.
Once empty, lower the bin back down and slide the outboard out...

Pop it on gas mark 5/180degrees/160 fan assisted and bake on the stand for 20 mins

[Cliff]

[quote="DaveRolph"]
When I go away I was thinking of taking a bin like Rogerblack, leave the engine on the boat and tilt into the bucket (propeller of for safety) then flushing with hose at home.

A bin like Roger Black? I saw one at the shops that might do.

Roger Black Bin.jpg (17.51 KiB) Viewed 1911 times