youen
Well-Known Member
Yesterday I have a look to a 1 GM 10. From 2003 low hours new exhaust elbow start at first but on the water à sort of black oily dash quite long to dissipate.Your thinks?thanks
Yanmar 1gm10
- Thread starter youen
- Start date
RichardS
N/A
How long since the engine had last been run?
Any smoke on start-up?
Any smoke when idling?
Any smoke when running at higher revs?
Richard
Any smoke on start-up?
Any smoke when idling?
Any smoke when running at higher revs?
Richard
Pords
Well-Known Member
These engine are renowned for corrosion in the cylinder head exhaust port. I had the same thing happening and it was only when I took mine apart I could see a hole where all the oil was being forced out through the exhaust. Expensive rebuild. Not saying this is the case but a 15 year old engine could be a possibility.
JumbleDuck
Well-Known Member
They all do that, Sir. Or at least mine always did, even when it had a brand new head and exhaust elbow.
Topcat47
Well-Known Member
There are no glow plugs on the 1GM10. Cold starting always involves a very rich mixture and, at least in my experience, unburnt fuel passes into the exhaust and out the back. This persists for many minutes as only when the water trap has been throughly washed through with cooling water and hot gasses will it completely disperse. Admittedly my cold start procedure is to run up the engine while decompressed until it's spinning over well,which exacerbates this tendency. Mine always likes a fairly wide open throttle to start, even when warm.
solent clown
RIP
Ours did exactly that today, scummy oily exhaust on cold idle. Quite normal. Topcat, I did the same this morning with the lever as it was very reluctant in the cold to turn over. :encouragement:
Tranona
Well-Known Member
1 GMs are often run at too low revs and never get really loaded. Therefore important to run them hard - close to 3000rpm and every so often a short run at maximum which could be as high as 3600rpm. You will then find that although there will still be signs of unburned fuel when cold it will disappear more quickly.
JumbleDuck
Well-Known Member
Absolutely. I used to give my an Italian tune-up every few weeks, which basically meant opening up until smoke started and keeping on until the smoke stopped again, after which performance was significantly improved. The first time I did this it took the best part of two hours before following vessels stopped needing their foghorns, but afterwards regular ten minutes or so was sufficient.
Porthandbuoy
Well-Known Member
JumbleDuck
Well-Known Member
That was you? I thought it was Vic 32.
Vic 32? Pfft. Amateurs. You could have hidden the Tirpitz under the smoke screen I laid down.
youen
Well-Known Member
Hi.Can you do your italian tuning on an old engine Which seems to have never been treated liké that.Did you risk to break something during the sea trial
solent clown
RIP
It is just an amateur decoke in the time honoured fashion, blowing out the cobwebs as it were. As long as you warm the engine it is fine. If something is fit to break it's going to break some time, better on a test than out at sea. I can remember adding a splash of brake fluid into the intake of an engine at revs to do a similar job, not recommended these days, but did a plodding old land rover engine the world of good.
Make smoke number one.
Tranona
Well-Known Member
Yes. As I suggested earlier the 1 GM needs to be run at higher revs than other engines partly because the power is limited at low revs and partly because it is salt water cooled. However it is often fitted in boats that are sailed more than motored so just gets short runs at low speed.
Run it under load at between 2500-3000 rpm to get it fully warm then 10 minutes or so at maximum revs. It would be useful to check that it can rev under load to at least 3400 rpm to check that the propeller is correct.
youen
Well-Known Member
At thé moment there is no revcounter on the engine is it easy to add?
JumbleDuck
Well-Known Member
I am sure I remember seeing something in the instructions saying "Thrash this engine mercilessly every so often" or words to that effect, but I can't find the passage now.
blackbeard
Well-Known Member
To Youen:
I have just added a TinyTach to my 1GM (make sure your supplier knows it is for a 1GM), seems to be fine, I have just found out that the idling speed was set way high! and has been adjusted; sea trials awaited.
(The fitting instructions say not to use the +12v supply to the engine, and suggest using the radio +12v supply instead, this leaves me a bit baffled but have done this.)
I have just added a TinyTach to my 1GM (make sure your supplier knows it is for a 1GM), seems to be fine, I have just found out that the idling speed was set way high! and has been adjusted; sea trials awaited.
(The fitting instructions say not to use the +12v supply to the engine, and suggest using the radio +12v supply instead, this leaves me a bit baffled but have done this.)
youen
Well-Known Member
How did you wired it?dix you need to calibrage the tacho ?
Spyro
Well-Known Member
I have a digital laser hand held rev counter. Less than £10 on ebay. Works on a small reflective strip on the crank shaft pully.
Appledore
Well-Known Member
Ditto. The revs seem to be just as they should be.
blackbeard
Well-Known Member
@Youen
TinyTach (diesel version) uses a transducer measuring pulses of fuel under pressure in the fuel pipe leading to the injector. So one wire from live side of transducer and another from its earth (taken as engine earth). Plus +12v power and earth. Takes hardly any current and doesn't need calibrating. Incorporates engine hours meter and timers indicating when maintenance due.
I though about one of those cheap tachs using reflected light but I needed something which would work under way without having to take the engine cover off (!).
TinyTach (diesel version) uses a transducer measuring pulses of fuel under pressure in the fuel pipe leading to the injector. So one wire from live side of transducer and another from its earth (taken as engine earth). Plus +12v power and earth. Takes hardly any current and doesn't need calibrating. Incorporates engine hours meter and timers indicating when maintenance due.
I though about one of those cheap tachs using reflected light but I needed something which would work under way without having to take the engine cover off (!).