aaarggghh.... the outboard - again!!!!

[jonathankent]

What a [--word removed--] of a day..... well it all started well, lovely clear blue skies, a very gently breeze, getting ready for our club race.... and for starters the tide is slower at coming in than normal, so a delayed boarding and potential late start of the race.... not too much of a problem, but niggling.

Then... got the boat all ready for the off, tried starting the outboard and it didn't want to play... found the cause, the fuel line not fully connected properly.... so got it started..... then no water cooling coming out the pee hole! /forums/images/graemlins/mad.gif just the odd drop, not the usual stream, even when increasing the revs it didn't improved, just dripped a bit more often..... [--word removed--] it - thats the race over then - can't go out on an almost windless day not knowing I can rely on the engine!

So, to the problem.... no water cooling passing through the engine. I imagine this is salt build up, or possibly something once living crawled up in there.... the outboard is left on the well all the time and has been anode protected for this. I haven't actually been out and used the engine for about 6 weeks (not had much time /forums/images/graemlins/frown.gif) but 2-3 weeks ago I did start it and let it run for 5 minutes or so. Do you think I am probably right in thinking some sort of buildup? Anyone any clever ideas on how to rectify this, without dismantling the whole thing? Any solutions I could use that could be pumped in to dissolve the buildup? Failing all that, I suppose I would have to strip it all down, check water pump & replace impeller, and try again, but as I have no experience with the mechanics of an outboard, and no manual (yet...), I would rather not have to if there is something else I can do.

Your help, as always, gratefully received.

P.S. the engine is a 1980s Honda 7.5hp

 

[philip_stevens]

Blow the cooling water system through with compressed air in the Pee hole. This should blow out any crap through the intake - this is the way it is done in outboard workshops.

If no crap or air comes out the intake, you can take it that it is completely blocked up. If air comes out, but subsequently not water when you run the motor, then it could well be the impeller knackered.

My Evinrude 4 Twin has recently had a reduced flow and quite hot water outlet from the pee hole, and this is what I did - now plenty of cool water piddles out.

Wasn't last weekend was it? Plenty of wind to start with, and then dropped to nothing. I towed a 22footer into Helford when his petrol engine wouldn't start. Sod of a swell all the way into the moorings - towed boat nearly surfed into my jacksie!!

 

[jonathankent]

No this all happened today...

I will give the blowing air into the pee hole a try... I don't think it is completely blocked up as I do get a dibbel coming through, but just not the usual stream.

 

[VicS]

I do not know the Honda specifically but maybe there are some aspects of this I can help with.

Firstly I think you will find that the pee hole is only a tell tale. The water coming out of there is only a fraction of the total cooling water flow, the remainder I imagine leaves via the leg with the exhaust gases.

The first thing is to clear any salt deposits from the pee hole with a bit of wire and if that is connected under the hood to the engine with a length of hose clear that and the connection to the engine as well but take care not to damage any plastic bits.

Then you need to determine whether or not the engine is overheating. That does mean giving it a good run either on the boat or in a dustbin full of water. .

As I do not know the engine I cannot tell you how warm the water from the pee hole should be but if there is any steam coming from anywhere then it will be a pretty sure sign that it is overheating. Similarly I do not know what sort of flow you should get from there. A good solid stream or jet I would suggest.

If it has not been changed for a while the pump impeller is something you must consider but there may also be a thermostat which has failed. However blockage of the water ways is alwys a possibility but I do not know if that is a particular problem on this engine.

As it is something that has occurred suddenly I would be hopeful there is nothing more wrong than a blocked pee hole.

If you do not know the age of the impeller it would be prudent to get it changed next winter as a precautionary measure.

What Philip Stevens suggests may help but unless you have access to a compressed air line then it may be a non starter

The best place for advice on outboards IMO is the iBoats forums where you will find separate boards for different engine makes. if you do go there post the full model details with your question including year hp and model number. Be patient with their new software as well!

I hope some of this helps but do report back when it is all sorted.

 

[jonathankent]

How does the thermostat work in the control of the cooling water flow expected from the hole.

By the way, I think it is a tell tale actually - if that makes any difference.

The tell tale / pee hole isn't blocked - my first thoughts. I have taken the pipes off and checked, as you say with a piece of wire. The dribble of water is coming from, what I believe to be, the main part of the engine, i.e. not just an overflow/recycle loop.... not sure I know what I am talking about, but makes sense to me.

I am looking towards the water feed to the engine, or the flow around the actual engine, but haven't a clue on how to take the engine apart to look into it.

I am sure something is wrong as it used to be a stream and is now just drops and an occasional dribble once the revs are increased.

I will have a look on the iboats forum.

 

[lancsjohn]

wear a rubber glove and put your finger over the pee hole to see if it builds any pressure. it would be better not to leave your engine in the water marine growth loves small openings.
Try www.iboats.com good forum for engines.

 

[VicS]

Ok it is not just a blocked pee hole. Pity.

It is still worth determining if the engine is overheating, IMHO, but it looks as though you are going to have to face up to the possibility of replacing the impeller and/or unclogging water ways.

Some people will suggest running some central heating boiler descaler (Fernox DS-3) through it. Some may even suggest the use of hydrochloric acid obtained as brick cleaner but I would not go that far ( I am a Chemist!)

If you are tempted to start taking things apart be very wary of shearing off bolts. It is the difficulty of removing bolts from aluminium casting that stops many outboard mechanics accepting engines as old as this for repair.

 

[Kawasaki]

She,s over 20 years old, be gentle with her! Like VicS said steel and zincy bits of alloy don,t mix so be carefull on the spanners. Sounds like constipation or impellor.If you have to go"stripping tease your nuts" with a wire brush, lubrication and a bit of heat sounds painfull but She,l need a bit of gentle pursuasion to "come "free. Good luck!

 

[misterg]

Might still be a blocked pee-hole - try jiggling a bit of thin wire, twig, etc. in the connection on the engine that the pee-hole tube connects to (with engine running if you're happy with this). It won't go in very far (20mm??), but it cured my 1990's 8 HP Honda of the same symptom.

For reference, this now has a strong stream from the pee-hole that's barely warm to the touch.

Our engine lives in a well, too. I presume that your engine is like mine, with the exhaust exiting behind the prop (rather than through the prop hub). If so, watch out for sea beasties clogging up the exhaust hole. Wasted a day last year, dismantling carb, etc. as engine would start & run, but died as soon as it was put under load. Evantually found out that the exhaust hole was full of mussels & barnacles. Engine fine after clearing these out.

Andy

 

[VicS]

Just an additional thought. you mentioned the little hiccup in getting it started. While sorting that you did not run the engine dry did you? That would destroy the pump impeller especially if it was getting a bit past its prime.

 

[jonathankent]

It was in the well all the time, so unless water wasn't pumped through it shouldn't have run dry. Any ideas where I can get a manual from?

 

[philip_stevens]

Jonathan,
try DM Marine as they are Honda agents in the Falmouth area.

 

[jonathankent]

Thanks for the suggestion/advice Andy. I have had the tubing off the engine outlet and poked around, as you say only just under an inch to go in.... unfortunately that didn't make any difference - I tried what I could on the boat, i.e. top and bottom, and couldn't fix it so came to the conclusion it must be more 'internal' to the outboard. I don't suppose you could offer any guidance on taking this apart, an annotated pic would be ideal... if possible.

Thanks for the exhaust tip. Mine is separate to the prop, same as yours. There were beasties living around it, but all cleaned out now. Shouldn't have gone any further as running isn't a problem.... I took the boat up the river a little to see if I could improve the water flow, unsuccessfully, but at least the engine is running OK and pushed me along fine. I could have continued out, but with a very weak water flow I thought it wise not to and best spend the time trying to fix it.... its home now as I can see a bit of 'surgery' coming soon.

By the way, as you keep yours in the well, how do you protect it from the fouling? Does normal antifouling work OK? This is something else to do before taking it back.... I don't really want all them back on next time.

 

[misterg]

[ QUOTE ]
I don't suppose you could offer any guidance on taking this apart...

[/ QUOTE ]

No, sorry. I'm aware of the general sequence of dismantling small outboards, but I've never done one. Happy with the mechanical side of things, generally, but after snapping bolts off working on motorbikes, I have a feeling of dread at the thought of trying to undo bolts that have been in aluminium & sea water for 20 years - I would almost do *anything* rather than risk trying to dismantle it (personal opinion, but see Kawasaki's reply, too). I don't think that its generally silted up, beacuse the change was sudden. It may be that there has been a failure of some sort, but it must be worth trying to clear a blockage with mains water pressure, or compressed air before dismantling. If the engine isn't over-heating, I might be inclined to use it as it is - the bulk of the cooling water exits with the exhaust, as far as I know.

You mention checking "top and bottom" - I assume by this that you've checked the water inlet? (Is it a cylindrical mesh screen, above the prop?)

[ QUOTE ]
.. how do you protect it from the fouling? Does normal antifouling work OK?

[/ QUOTE ]

I was wary of using normal (copper) anti-foul on an aluminium leg, so I gritted my teeth very hard and bought a tin of Trilux hard antifoul that claims to be suitable for aluminium. (18 quid for a boot-polish sized tin /forums/images/graemlins/mad.gif) The little sods love it!. 1st year wasn't so bad, as I didn't prepare the leg very well, and most of the trilux flaked off, together with the barnacles. Did a better job in subsequent years, and it just seems to act like a primer to improve their adhesion /forums/images/graemlins/frown.gif. I need to scrape them off the prop a couple of times a season, so just do the rest of the leg (and the exhaust) at the same time - all reaching under the boat from the dinghy. Don't think I'll bother carrying on with the trilux.

There is an American site that is sometimes referred to on here, which deals exclusively with outboards, but I can't remember what it's called at the mo.

edit:
[ QUOTE ]

BTW an excellent source of help and advice on outboards are the iBoats forums where you will find separate boards for different makes of engine. If you go there with a question always quote the full model details including the model number if possible. Be patient with them though. They recently switched to new software and it seem to take ages for the index pages to load but once you get to the board you want it seems to run OK

VicS (21:38 13/07/2006)

[/ QUOTE ]

But you already know this, because you've posted a question there /forums/images/graemlins/laugh.gif!

Good luck !

Andy

 

[VicS]

Further thoughts:

You mentioned somewhere , iBoats I think, that your mooring is a drying one. On the Helford river I imagine that is into some soft mud. Does the boat sink in to the point that the prop, gearbox etc sinks into the mud. If so then take a good look a at the water intake etc. It could well be that it is blocked with mud, stones and marine life. It may be difficullt to clear if that is the case, and the most effective way of jetting it clear will depend on the geometry of the intake and strainer.

It might be worth connecting a powerful hose onto the pee hole connection on the engine and giving it a good blast but all that may happen is that water will go out via the exhaust outlet. At least that will prove that the problem lies upstream of the pee hole rather than down stream. If you get water out both ways ie from the exhaust outlet and the water inlet then that'll rule out blockages and you will need to look at the pump impeller.

Keep the engine upright while messing about with water from hoses as you won't want to risk getting water into the cylinders.

Re antifouling: you should not use a copper based AF on aluminiun. That is why Trilux or similar is recommended

 

[jonathankent]

Yes the mud is very soft.... the keel/bilge plates sink right in to the bottom of the hull, about 12" or so. It doesn't go quite as far in at the stern, only helf way up the rudder, but I imagine that the bottom tip of the outboard may go in... I don't think the prop does because that is too high up and the mudline only goes half way up the rudder/skeg.

I am deffinitely going to try what I can to clear it without dismantling. Do these little meshes for the water inlet come out for cleaning? There isn't any growth on it, but it isn't completely clear either. A hose pipe tonight it is then.....

 

[VicS]

I was thinking that if the thing sunk in far enough mud could be forced right in up to the water pump and even up what is probably a small diameter tube above it. From what you say that does not seem likely but something may have crawled in or got sucked there and got stuck if there is not a fine enough strainer.

The day to get the spanners out beckons!


No joy with iBoats yet I see. The Honda board does not seem to be very active. I guess they are not so popular in the USA. I'm sure if you asked a similar question about an Evinrude, Johnson or Mercury there would have been plenty of replies.

 

[jonathankent]

I know you don't know this particular engine, but is it a relatively simple job to drop the bottom off? I might be wrong, but isn't the water pump in the bottom of the leg normally and could save me dismantling anything in the top of the 'engine'?

 

[VicS]

As you say i do not know this particular engine so It would not be right for me to comment.

I would expect the pump to be mounted on the top face of the gearbox with the (vertical) drive shaft passing through the impeller. So in theory all I would expect to have to do is drop the lower unit off BUT.....

I took my Evinrude apart, lower unit off to get at the pump etc and the power head off to actually get to the particular problem I had (the lower unit had to come off before the power head anyway) without any reference to manuals etc. but I am the sort of person who is likely to take things apart just to find out how they work. Sometimes they never do again of course. In the case of my 'rude I took it to bits correcctly the first time but the second time I did it incorrectly and was lucky not to have smashed the pump housing.

 

[misterg]

[ QUOTE ]
Do these little meshes for the water inlet come out for cleaning?

[/ QUOTE ]

As far as I can tell, they come out from inside, after you've dismantled the lower leg /forums/images/graemlins/frown.gif. The mesh is quite fine. One trick I found is that you can turn the mesh around to expose a fresh bit in the "window" in the casting (use something pointy to gently spin the mesh around) got me out of jail when I painted it with anti-foul once, and completely blocked it /forums/images/graemlins/blush.gif

The only thing I've come across which is vaguely relevant is this:

[ QUOTE ]
These motors also plug up at the telltale and if it doesnt flow after the new one is installed ,put compressed air @30 psi right into the outlet while running.The motor stopping indicates no cooling so do drop the lower unit and put in the new one.Mark the little shift shaft with a pencil or feltpen BEFORE you drive out the little pin(lower one leaving the connector to the upper as it wont fit thru the grommet!),then the lower assy. slides down to reveal the water pump.DO NOT remove the plastic block below the water pump housing as it has the drive seal which you dont want to touch!Goodluck!
TM


[/ QUOTE ]

from a search on the iboats forum (buried deep !) Don't know what he means by "new one installed" - maybe impeller?.

Andy