Yanmar 1GM

[copaco]

Hi!There is no SN on my single cylinder Yanmar.1 GM is not embossed on head,just the number 3.Somme say it is an industrial Yanmar.
What I don't see in the shop manual is the absence of an oil filter.There is a wingnut on what would be an oil strainer(?).If I turn it nothing happens.The problem I have is ajusting the throttle after the injector and fuel injection pump have been rebuilt.Does anyonne know what exactly is this Yanmar, in a 1980 Mirage 27 sailboat.Thanks.

[Lowcountry]

I had an Alerion Express 28 with a 1GM10 in it. It had an oil filter at the bottom left when looking at the engine from the front. Do you have a photo of the engine?

[copaco]

Hi Lowcountry,I'm not familiar with posting photos on forums.Even if you are not Facebook I believe you could see a photo I will publish on my FB page.Lionel Cormier (with wind rose)

[Wotname]

The 1GM and 1GM10 both have conventional spin on oil filter.
The preceding vertical single cylinder model was the SB8 (& SB12) and this engine had a "T" handle oil stainer (i.e. not a conventional single use spin on oil filter).

You may have a SB engine as the 1GM and SB looks sort of similar (from a distance ).

However, there many differences and the gearbox/clutch assembly is quite different as is the injector pump. Here is a running SB8, the SB12 is a little bigger.

https://www.youtube.com/watch?v=bBEV0bqJRgE

[Wotname]

Originally Posted by copaco

.......The problem I have is ajusting the throttle after the injector and fuel injection pump have been rebuilt.Does anyonne know what exactly is this Yanmar, in a 1980 Mirage 27 sailboat.Thanks.

If the injection pump look anything this, then you don't have a GM series but most likely have a SB series engine.

[Wotname]

Some further info which might help identify the engine.
SB 1976 to 1980
1GM 1980 to 1983
1GM10 1983 to 2009

[Wotname]

Originally Posted by copaco

.....
What I don't see in the shop manual is the absence of an oil filter.There is a wingnut on what would be an oil strainer(?).If I turn it nothing happens...........

The older Yanmar oil strainer looked liked this but perhaps the T handle has been broken off and replaced with a wing nut. When the shaft is rotated (by the T handle), the inside discs turn and any crud caught on the outer edges of these discs are wiped off the the smaller stationary leaves. The crud falls into the strainer housing which should be removed cleaned occasionally. The T handle should be rotated a couple of turns before every start.

This is from a different engine (a YSE) but the basic stainer was used on several Yanmar models including the SB.

[Wotname]

Originally Posted by copaco

Hi!There is no SN on my single cylinder Yanmar..........The problem I have is ajusting the throttle after the injector and fuel injection pump have been rebuilt.Does anyonne know what exactly is this Yanmar, in a 1980 Mirage 27 sailboat.Thanks.

A 1GM and 1GM10 should be a straightforward process to adjust the throttle while the SB is somewhat more problematic and you really need to follow the manual exactly to get it even in the ballpark.

Once you have positively identified your engine model, you will have a better chance of getting sorted.

[copaco]

Great thanks Wotname.I have downloaded the manual .The ajustment procedure and start sequence, well explained.Sure is a good side to Facebook.I,m in saltwater and wonder if a heat exchanger could be fitted.

[Wotname]

Originally Posted by copaco

Great thanks Wotname.I have downloaded the manual .The ajustment procedure and start sequence, well explained.Sure is a good side to Facebook.I,m in saltwater and wonder if a heat exchanger could be fitted.

My opinion - don't bother to fit a heat exchanger.

The engine was designed for salt water cooling and providing you replace the anode regularly and occasionally the flush the head/block with a descaling agent, it will last for almost forever.

To fit a heat exchanger you will need a different thermostat arrangement, a coolant pump and a header tank. The thermostat is the more difficult issue. OK, it is not impossible but the reward is low!

Was it a SB engine or something else?

[copaco]

Yes, a Yanmar sb8.Regards.

[copaco]

Yes an SB 8.
Punch mark on connector helped to ajust the regulator.
The wires from the inst.panel were cut so how to stop engine?
The Yanmar dealer says to use oil 5 W 40 (non synthetic) in both engine and gear box,!!
The mixing elbow must be replaced so can the water lock be inspected?
The idle is on the throttle, I presume ,but I saw something about a bolt on a governer?
I’m up in Canada ,by the way.Thanks for your knowledge.

[Wotname]

Originally Posted by copaco

Yes an SB 8.
Punch mark on connector helped to ajust the regulator.
The wires from the inst.panel were cut so how to stop engine?
The Yanmar dealer says to use oil 5 W 40 (non synthetic) in both engine and gear box,!!
The mixing elbow must be replaced so can the water lock be inspected?
The idle is on the throttle, I presume ,but I saw something about a bolt on a governer?
I’m up in Canada ,by the way.Thanks for your knowledge.

The engine is stopped by moving the regulator arm from idle to stop. i.e. the regulator essentially has a range from stop to idle to full power. There is no seperate engine stop mechanism (electrical or mechanical).

This engine has a very simple injection pump and all functions (stop, idle and full power) are achieved by moving the regulator arm on the injection pump!

The governor is also attached to the same arm.

You will see how the engine is stopped at 1.34 on the youtube video linked above.

The gearbox and the engine uses the same grade of oil (but in different sumps).

5 W 40 is suitable if it has a "CD" or higher rating and most oils do have such a rating. Depending on ambient air temperature, a single weight 30 oil will also be suitable.

The water lock will be "downstream" of the mixing below so it can be inspected any time you have the exhaust components apart.

[Compass790]

Originally Posted by Wotname

My opinion - don't bother to fit a heat exchanger.

The engine was designed for salt water cooling and providing you replace the anode regularly and occasionally the flush the head/block with a descaling agent, it will last for almost forever.

To fit a heat exchanger you will need a different thermostat arrangement, a coolant pump and a header tank. The thermostat is the more difficult issue. OK, it is not impossible but the reward is low!

Was it a SB engine or something else?

Yes I agree with Wotname, dont bother with heat exchanger just make sure you keep up with the anode. Our 1980 yanmar ysm8 ( very similar engine with a lot of common parts) has little corrosion & has been in salt water all it's life.
If you keep it in a marina berth its a good idea to set up a tee & valve in the water intake line to fresh water flush it but even that is probably more to make the owner feel good.

[copaco]

Great Wotname .Very helpful and appreciate it very much.Starts my day on a good footing.