Thames Mechanic

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vjmehra

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Does anyone know of any mechanics I can visit on the tidal Thames (not Chas Newens), I just want someone to take a quick look at our engine?
 
Very kind of you offer, well we've been experiencing a lack of power and a very inefficient fuel economy rate. From what people have told me it sounds very likely to be a flooded carb...
 
If it's a Petrol, it may have a CV carb, with a diaphragm on the top (Typical to old Volvo) which may have split. Replace, or do a quick fix with silicone sealant! (Three screws on top of each carb, lift carefully, don't lose spring)

Other basic check include cruddy Distributor cap contacts (And rotor arm, just clean up with nail file or sandpaper) Dirty Air filter, or knackered plug leads.

BE CAREFUL!!.....if the rotor arm/ dissy cap or leads are 'leaking' stray sparks may cause huge explosion if any fuel vapour/ lpg gas is present in engine bay!!

Also, the choke may have stuck on. Check the flap open up when choke is in 'off' position.

Those are usually easy to find and fix. You might find other things such as:

1/ Valves need adjusting

2/ Fuel pump, if engine mounted, is leaking fuel into engines sump, making oil smell of fuel (running rich as a result!)

Check plug colour after hard run, should be light biscuit colour, not black and sooty. I'm assuming you have good plugs...
 
What engine? Volvo/mercruiser etc. inboard/outboard? I can have a look, but not outboard. In Fulham on W.E.
 
Its a Yamaha 60FETO (2 stroke, 3 cylinder outboard)...so sounds like its not your thing, but many thanks for the offer!
 
hi
i dont know the bigger yamaha's too well,but if it is similar to the larger honda's it may have several carbs.

is the petrol fresh?
out boards with multi carbs. will have very small jets,and over the years the idle and transfer jets can become partially restricted by varnish deposits.

the engine may be relying on the main jets,causing excess fuel to be burnt.

the running behavior you descibe is likely to be caused by stale fuel.
try dumping the current fuel and replenish with fresh stuff purchased from a roadside filling station.
 
The fuel is fresh, we always disconnect the fuel tank and run the engine to get all fuel out of the system at the end of every session, so (in theory at least) the fuel every session is fresh!
 
check if you have spark in all cylinders, if flooded carb is the problem then a simple carb rebuid should sort out your problem.

The mechanic in boat shop in Teddington Lock should be able to help you. But it is a simple job really, adjusting the float in the carb as the needle is most probably stuck.
 
Hello All, I co-own this RIB and am bordering on feeling competent enough to fix this problem myself.

A blurry attachment shows our three spark plugs. The suspiciously clean one is the lowest. To my eyes, there wasn't much discernable colour (tan/black/white) on any of them, but there was a little "carbon-esque" deposit on the clean one. They're NGK B8HS-10's. I'm presuming this confims the diagnosis suggested here.

The solution, I gather, is to pull out the three carburetors, open and clean the float chambers (the lower bowl shaped part of each carb') with a fuel-soaked rag, then replace and rebuild.

The diagram is pdf page 51: http://motorka.org/doc/yam-remont-50-90.pdf

Rebuilding: I presume it's very important to rebuild with a torque wrench. I'm slightly concerned over how delicate the settings on "throttle arm" (the rod(s) connecting the three carb's, controlling the throttle), etc., when I reattach.

It's pretty fiddly in there from my first look.

Any thoughts or advice?

Much appreciated

Craig
 
Stick your post on Ribnet - I suspect you'll get more members with an outboard in your power range.

CJL
 
Why not go to Chas Newens?

Paul there very knowledgeable and regularly services my Mercruiser, and they look after a lot of local outboards.

I've always found them competent and good value considering their location.
 
Only a truly fouled Spark plug will cause issues.

I'm afraid you're dreaming!

Seriously, don't f@ck around with big outboards unless you really understand them. Not only are you risking further damage, but you'll mask the original problem, and make it more hassle to repair!
 
craigmiranda said:
Hello All, I co-own this RIB and am bordering on feeling competent enough to fix this problem myself.

A blurry attachment shows our three spark plugs. The suspiciously clean one is the lowest. To my eyes, there wasn't much discernable colour (tan/black/white) on any of them, but there was a little "carbon-esque" deposit on the clean one. They're NGK B8HS-10's. I'm presuming this confims the diagnosis suggested here.

The solution, I gather, is to pull out the three carburetors, open and clean the float chambers (the lower bowl shaped part of each carb') with a fuel-soaked rag, then replace and rebuild.

The diagram is pdf page 51: http://motorka.org/doc/yam-remont-50-90.pdf

Rebuilding: I presume it's very important to rebuild with a torque wrench. I'm slightly concerned over how delicate the settings on "throttle arm" (the rod(s) connecting the three carb's, controlling the throttle), etc., when I reattach.

It's pretty fiddly in there from my first look.

Any thoughts or advice?

Much appreciated

Craig
Click to expand...


I had exactly the same problem, on a Yamaha 70hp 2 Stroke. Two possibilities; one is that your fuel pump gasket is broken and fuel is just leaking into the bottom cylinder.

But it is quite rate unless it has been under stress (the fuel pump).

Another possible (it was my problem) problem is your bottom carb is flooded. The floater inside the carb need to be just be put in its original place on the needle.

Don't worry too much about adjusting etc. Try remembering how many turn each screw is twisted when openning the carbs etc. Then after rebuild when the engine idles, you can adjust it later.

Having said that, the mechanic in Putney does only charge £150 for a full service on your outboard so why not give it to him?!
 
Hello All, thanks for the advice - it's greatly apprecaited.

Although I'm keen to dip my spanner in, I simply must fix the problem this weekend, so i think I'll have to get to a mechanic.

The issue I now have is that we don't have a trailer (because we don't have a car), so we're limited as to which mechanics can help us. The way it drinks fuel, I'm not keen to go too far a field either.

I will try Bill at Teddington Lock and/or Chas Newans, but other suggestions in the radius of Kew are very welcome. The RIB and I will be just by Kew Bridge this weekend.

Newtothames, do you have a name & number in Putney?

Cereal tiller, that's an extremely kind offer, but perhaps the distance to too much.

thanks again

Craig
 
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