Could the same apply to a Honda outboard?

Sans Bateau

Sans Bateau

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Bit of a crossover here, but this may help anyone with a Honda Outboard.

I've just collected my Honda lawnmower from the repairman. Normally, just about any mechanical problem I can sort out. But, last year the engine started to misfire and splutter after a little work. To me it had all the symptoms of a fuel problem, so I striped down the carb and cleaned the fuel lines, all seemed OK. By now the engine was a pig to start, so as I had no time I took it into the lawnmower repair man.

His diagnosis and fix? A new spark plug!!!!!!!!! /forums/images/graemlins/shocked.gif
 
[ QUOTE ]
may help anyone with a Honda Outboard

[/ QUOTE ] Any outboard .... any petrol engine.

One of the first and easiest things thing to check when any petrol engine is mis behaving. Followed by points if it has them.
 
Hi Galadriel

Not as daft as it sounds - and you're right, it IS a fuel problem...'but not as we know it, Jim'.

I've just been researching small outboard problems for the next issue of PBO, and spark plugs do come into it. Without giving too much away (we want you to buy the next edition!) it is all to do with the temperature rating of the plug, and that is as a direct result of the effect of modern fuels. If your (small) outboard is being temperamental, swap the plug out for a slightly hotter one ( ie BH5HS for a BH4HS) and see what happens. (Check manufacturers ratings first so you really are going hotter.)

As another fix ( and this applies more to road vehicles) if your engine seems a bit sluggish or has flat spots, damn the expense and try it with a tank of 'super' 97 octane, rather than the usual 'premium' 95. The quality of the bottom-end fuels has a lot to do with what's been added. More in July's PBO.

Jake K
 
[ QUOTE ]

As another fix ( and this applies more to road vehicles) if your engine seems a bit sluggish or has flat spots, damn the expense and try it with a tank of 'super' 97 octane,

[/ QUOTE ] I'll try that on my diesel Grand Vitara. Thanks for the tip.
 
Yep, you are right!! A friend of mine asked me to look at his Honda 2hp outboard just last weekend because his motor, having worked perfectly the day before, simply refused to start or even fire.

The first thing I asked was 'have you checked the spark plug'!

'Yes' he said, 'and it's giving out a fat spark'. So we moved on to strip the carb etc etc.

Nothing worked and the engine still refused to start, but the spark plug, held against the casing, gave out a huge spark. So it couldn't be that .................... could it?

Eventually we gave up, but I suggested he spoke to a mutual friend of ours who also has a Honda o/b.

He did. 'Spark plug', the chap said, 'Never mind that's it's sparking OUTSIDE the pot, I'll bet that's what is is'.

It was exactly that. My friend put a new one in and the engine fired instantly!

For my benefit, does anyone know why this happens? Something to do with pressure .....?
 
I don't know about modern conditions, but when fuel went unleaded some of the additives (was it sulphur?) were coating the insulators on the plugs and causing tracking under cylinder compression conditions. You couldn't clean the plugs, just had to bin them.
All those plug-blasting machines became redundant overnight.
 
[ QUOTE ]
swap the plug out for a slightly hotter one ..............Check manufacturers ratings first

[/ QUOTE ]

I hope this forth coming article will either explain the different manufacturers' codes or tell us where to find it, or preferably both.

I know Champion and NGK numbering run in opposite directions but I can never find the info to tell me which is which. I have not a clue about other makes.
 
In my RAF days we checked plugs on a machine that showed you a plug working under presure and a lot of them worked ok in the open but failed under presure.
 
Yes so it seems. In fairness, the plug must be 6 years old, That said, the spark plug in my Johnson 2T outboard, 12 years old. And in an old Victa Lawnmower (2T) went for 18 years of rough abuse! It may still be working now for all I know, I left it at the house when we moved.
 
[ QUOTE ]
I know Champion and NGK numbering run in opposite directions but I can never find the info to tell me which is which. I have not a clue about other makes.

[/ QUOTE ]

Fill yer boots

Cheap place to buy them from, too.

Andy
 
IMHO changing the heat range of the plug in a small outboard and /or sticking a higher octane fuel in, tells Me that something else is amiss.

I first came across 'it fires outside but not inside' syndrom whilst getting blue in the face trying to start My Greaves up to the footrests in a Welsh bog in 66!
During 30 years in the Motorbike trade, I must have binned thousands.
Not only was it good business for Me NKG ,Champion et al, at least peeps bikes would start!
As a biker Jake you will understand this.
Changing heat ranges on perfomance engines can be critical, but will make hardly any noticeable difference to a put put outboard.
In fact go to 'Hot' or 'Hard' as we used to say and problems then could occur with the little put put warming up.
Don't ferget most outboards used for tenders don't run for very long at anyone time.
Unless the pub or moorings are 3 miles away!

Yep yer right again VicS the Champs go down ref the NGK's go up.
" " " " " " any outboard....any petrol engine.

Lakey We stopped using those Sand blast gadgetts ages ago.
OK fer Moggie thou at the time they would prolong plug life for while.
Even in the early 70's I noticed the plug on My Bultaco would only last a few laps after I had blasted it in those gadgetts.
Running on a Shoe String everything was tried to save a few pennies.
Soon learned that was false economy.
I think the porcelain on the centre electrode was damaged/ weakend.
Never looked into it. Just stopped blasting!

Having said that the plug on My little Yam is 8 years old and She runs OK.
100/1 mix,clean the carb annually, etc etc but have a new plug at the ready always! /forums/images/graemlins/grin.gif
 
Hey that's handy misterg, thanks.
I was going to nip down to see the Guys in My old Motorbike shop and get a copy of the Comparison book they use.
Well I think they still use it.
Mind You, they are probably 'Up to Date' like you and can click on stuff for answers.
This Dinasour can't! /forums/images/graemlins/blush.gif
Need to send a PM to someone now, I offered Him a copy, modern technology
Bloody marvelous /forums/images/graemlins/grin.gif
 
Kawasaki has just about said it all, and has many more years bike experience than me, but my first job after leaving Uni was running the workshop at a small Honda/Yamaha dealers..(so my degree was in Politics...but who cares /forums/images/graemlins/grin.gif)

In would come the punter with their rough running Honda fours, and out they would go as sweet as a nut for the price of four NGKs (We found Champions less consistent so it was was NGK 100% for us). We also had a plug cleaner and tester...what a waste of flipping time that was!

Tim
 
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