Possible budget Yanmar 1GM installation: advice needed

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davesparkes

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Hello,

I am considering installing a small diesel inboard in our family's Hunter Duette, as my father is getting on in years and messing around with an outboard is getting too much for him. I have secured used Yanmar 1GM to use as the basis for a budget installation, and I was hoping that forum users could provide some sage advice, mainly regarding:

1) The best places to find either good used or budget new installation items: prop, sterntube, seal, p-bracket, exhaust, engine controls, fuel system, etc.
2) General installation do's and dont's
3) Guidance on prop size; a quick look at an online prop calculator suggests a two-bladed prop of 11x7 size would be about right?
4) Engine overhaul advice - the engine is a runner, but I plan on removing the head to perform basic checks/servicing/overhaul

Very grateful for any advice!

Cheers,
Dave
 
I can give you the operation manual for the 1GM10 if you don't have one.It is terribly laid out as it includes 5 languages but it might give you a start.I now have a Beta engine.I would say Beta excel in providing installation information which would add to your knowledge of the common factors to consider and this is available for free download on their site.
Send a PM with address if you want the yanmar manual.
 
davesparkes said:
Hello,

I am considering installing a small diesel inboard in our family's Hunter Duette, as my father is getting on in years and messing around with an outboard is getting too much for him. I have secured used Yanmar 1GM to use as the basis for a budget installation, and I was hoping that forum users could provide some sage advice, mainly regarding:

1) The best places to find either good used or budget new installation items: prop, sterntube, seal, p-bracket, exhaust, engine controls, fuel system, etc.
2) General installation do's and dont's
3) Guidance on prop size; a quick look at an online prop calculator suggests a two-bladed prop of 11x7 size would be about right?
4) Engine overhaul advice - the engine is a runner, but I plan on removing the head to perform basic checks/servicing/overhaul

Very grateful for any advice!

Cheers,
Dave
Click to expand...

I fitted a 1gm in my Stella some years ago, not as difficult as I thought it was going to be but I probably spent more time thinking about it than actually doing it.
Before you start any major overhaul, check prices for spares. I tried to overhaul my 2gm 2 years ago. Spent a fortune on parts before deciding to scrap it. Things like head gaskets and thermostats are eye watering. If it ain't broke, etc.
I can't help with sourcing 2nd hand parts, but you could easily spend lots of time and money on parts that aren't suitable or are worn out, so be careful.
I assume a Duette doesn't have a skeg so a 3 bladed prop would be my choice, the size and pitch is about right, it's a bit of a black art though.
 
Last edited:
Hello Dave, and welcome.

You will get a great deal of help on here, but for starters :

http://j30.us/files/yanmar-manual.pdf Operation Manual

Barrus: Maunal Downloads:

https://www.barrus.co.uk/divisions/marine/diesel/yanmar-marine/manual-downloads/

Youtube: Several handy ones on the 1GM

PBO Magazine Sept 2013 - Remove and refit a Cylinder Head.

I have a Yanmar 1 GM in my 22 footer, and do all the servicing and replacement bits myself. Many engine parts are available on Ebay, for instance, and do not always purchase the more expensive Yanmar pieces. For instance, their exhaust elbow is over £200, but there is a stainless steel one available from the USA for about half that! Filters; car filters are much cheaper, as are alternator belts - about half price, so do shop around or ask on here.

As for your prop and so on, sorry I can't help there, but someone will be along soon, LOL!

Most importantly, ensure when you install the engine that you use the correct engine mounts (not necessarily the Yanmar ones), and the engine is correctly levelled, etc.


Hope some of this is of help to you.

Geoff
 
I had a 1GM in an Impala 28.
An amateur conversion from 'outboard in a well'.
It was noisy, vibrated a lot and basically was not a pleasant way to make progress.
Given the improvements in 4 stroke outboards, maybe an outboard in a well might be better.
I don't know what your costings are like, but a new 10HP electric start motor looks about £2500.
Which is a fair pile of dosh of course.
But it might be a lot less work?
Just a thought.

In my view, any sailing boat should have a folding or feathering prop, or an outboard which lifts clear of the water. I believe the Impalas lifted their outboards on a sliding doofer with a pulley system, then filled the hole with a fairing piece?
 
The installation cost should in theory not vary much regardless of which engine you have
BUT
a second hand unit may well have cost of normally supplied with engine parts
EG mounts couplings stop cables etc,
Plus you may also find that some engines use larger than required exhaust & water systems because they use the same across a range of HPs
The 1GM is probably the smallest engine in common use so for example new 20mm sterngear might not be as expensive as buying a used 25 or even 30 mm shaft and having to buy larger than required tube and bearings or used that because they are part worn require replacing in the near future
The one thing that must be correct is the prop size and again price goes by Diameter and boss size.

Possibly start with new costs and if you can get good used then you may win a watch
 
Welcome to the forums, Dave. You asked for general dos and don'ts - my advice would be don't even consider it! The work involved is immense, and the chances of a satisfactory result are slim, as lw395 has also suggested. The costs involved are significant, too, in the region of a few thousand even if you do a lot of the labour yourself. If you need to make life easier for your father, an electric start outboard is the way to go. If he can't cope with that, change the boat. But don't start trying to carve the boat up yourself, it'll end in tears.
 
I'm currently doing a budget engine install, though not with a 1GM.

Don't automatically take the head off. Do a compression test first (make sure the gauge is not petrol only!) and if that's within tolerances then just give the engine a thorough service and flush the cooling system through with Rydlyme (an excellent descaler).

It'll make your life much more simple if you make an engine jig. Doesn't need to be beautiful, just the critical measurements like the relationship between mounting points and the gearbox output flange together with overall length/height/width. It can be knocked-up out of old off cuts and will be worth its weight in gold. Once you've made engine beds and aligned everything using the jig, you'll know that when you come to fit the engine proper it should line straight up with just a little jiggling necessary.

That said, and I'm assuming the boat hasn't been fitted with an inboard previously, once you've made/fitted a stern tube/engine/controls/tank/exhaust etc, your going to be faced with a decent sized bill. A previous post suggested your father looks at the possibility of an electric start 4-stroke outboard. That would be worth investigating I think.

I
 
Got to say 'Don't do it' The 1GM is pretty old and I have just replaced a friend's one with a 1GM10. Unless you are competant on the complete instalation (Major Clanger, above) It will cost far more than the boat is worth. The idea of installing a complete inboard set up, with the stern tube etc, is interesting, but VERY costly if you can't do it yourself.
When we first tried to sort the 1GM, even a head gasket cost £60! And getting a new valve seat fitted, along with the valve, cost over £200. It would have been acceptable, if it had continued to function, but, after a while, something else caused it to overspeed, so we moved on, and found a more recent engine.
 
pvb said:
...! The work involved is immense, and the chances of a satisfactory result are slim, as lw395 has also suggested. .....
Click to expand...
To be fair, I wouldn't say the engine in my Impala was 'unsatisfactory'. It worked. It propelled the boat against the tide, it gave me confidence to go further than I might with an outboard, especially an outboard from that era. The previous owner had done the conversion in order to have motoring range back from cross-channel races withoout carrying gross quantities of fuel. It motored me across Lyme Bay at least once.
I certainly used it in rough conditions where I wouldn't trust an outboard on the transom, and it didn't miss a beat.
I was not unhappy with it, but I'm an 'engine is last resort or for in/out of harbour' kind of sailor. I wouldn't choose to set off knowing I had 10 hours of motoring with it, I'd prefer to amend my plans.
But thrashing against the tide in Portsmouth entrance, I was well pleased to have it.

It seemed rough to me, and I owned a BSA 650 at the time, but you don't run that for hours on end at fixed RPM I suppose. My mate had a 26(?)ft Beneteau which was far more civilised under its factory installed motor.
Installation wise, it was basically all out of the vetus catalogue. 25 litre fuel tank under the Stbd quarter, plus a few 5l cans. The usual CAV filter. A nice fat battery just for starting. Control panel somewhere ridiculous....

On another point mine was AFAIK, a 1GM10. Some people use '1GM' to include the 1GM10. I'm vague about the difference TBH.
 
Hi Guys - thanks very much for the advice. I have seriously looked at electric-start outboards, but the Duette has quite a small outboard well, and even the smallest elec start (Tohatsu 8) is far too large to fit. Ditto the Torqeedo - it’s too long to fit without major GRP surgery.

I did investigate the Torqeedo pod drive, it looks like an excellent piece of kit, but cost and the lack of shore power connection for charging put paid to that idea.

We had a 1GM in our Seawolf 26, it was a great motor and never gave a minutes trouble. I am aware of the usual 1GM weaknesses.

I am reluctant to move on from the Duette as in every other way she is perfect for us - bilge keeled, manageable, fast for her size and pretty. We did look at an inboard H23 but I couldn’t live with the chunky looks, sorry to any owners out there!

Can anyone recommend a book which can help with installing an engine from scratch? I’m sure I used to have one, but cant find the damn thing now!

Cheers
Dave
 
davesparkes said:
....
Can anyone recommend a book which can help with installing an engine from scratch? I’m sure I used to have one, but cant find the damn thing now!

Cheers
Dave
Click to expand...

ISTR it's covered in a book I read 'Start with a hull'.
Probably other how to fit out a bare hull books too?
I think I'd look at Larrson and Elliasson as well.

I would think the big issue will be weight distribution, which means wanting the engine fairly forwards?
Then the big difficulty is carpentry to cover it up to an acceptable standard.
If it's possible to do more about noise and vibration it would be a bonus IMHO.
 
I have "How to install a new diesel" by Peter Cumberlidge. Fairly commonsense stuff but handy to have it spelled out. Much of the illustrations and photos are more relevant to wooden boats.
You are welcome to it if you PM me your address.
 
davesparkes said:
Hi Guys - thanks very much for the advice. I have seriously looked at electric-start outboards, but the Duette has quite a small outboard well, and even the smallest elec start (Tohatsu 8) is far too large to fit. Ditto the Torqeedo - it’s too long to fit without major GRP surgery.

I did investigate the Torqeedo pod drive, it looks like an excellent piece of kit, but cost and the lack of shore power connection for charging put paid to that idea.

We had a 1GM in our Seawolf 26, it was a great motor and never gave a minutes trouble. I am aware of the usual 1GM weaknesses.

I am reluctant to move on from the Duette as in every other way she is perfect for us - bilge keeled, manageable, fast for her size and pretty. We did look at an inboard H23 but I couldn’t live with the chunky looks, sorry to any owners out there!

Can anyone recommend a book which can help with installing an engine from scratch? I’m sure I used to have one, but cant find the damn thing now!

Cheers
Dave
Click to expand...

Did any Duettes come with inboards? If so, sell your current boat and buy a different Duette. If you're shying away from 'major GRP surgery' involved with the Torqeedo, then just wait until you have to design/make/fit engine beds, and bearers for the shaft and cutlass bearing. Hats off to you if you really want to do it, but be in no doubt of the scale of the undertaking.

Whereabouts is the boat?
 
davesparkes said:
Hi Guys - thanks very much for the advice. I have seriously looked at electric-start outboards, but the Duette has quite a small outboard well, and even the smallest elec start (Tohatsu 8) is far too large to fit. Ditto the Torqeedo - it’s too long to fit without major GRP surgery.
Click to expand...

The Torqeedo Travel doesn't have to have the tiller bit attached for it to work, so I'm fairly sure it would fit in the outboard well. Torqeedo sell a remote throttle kit for it, too - https://www.torqeedo.com/en/products/accessories/cables-and-steering/remote-throttle/1918-00.html

I have a Torqeedo Travel 1003, and it's an excellent bit of kit.
 
It would probably be far easier to mod the well to take the 8hp electric start outboard, than build every thing for an inboard. As M.Clang says: Engine beds, prop shaft bonding, not to mention buying a new shaft and log, cutlass and drip seal. I would think that (as a tinkerer..) fitting an electric start to the existing outboard would be much easier.
 
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