removal of engine

stevemeakin

stevemeakin

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6 Jun 2007
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Maldon, Essex
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Due to a lack of compression in my Yanmar 1gm (9hp) I'm going to remove the engine and have it rebuilt. Having never removed an engine, I wondered whether the forum had any tips, tricks or even watch our for's as I want to make sure it's as painless a process as is possible

Thanks in advance
 
The actual removal of the engine is straightforward - but varies from boat to boat on how the engine is lifted out.

Mine for example came through the cockpit floor which had to be removed, others will fit through the companionway hatch.

As for disconecting the engine from the boat it is best to be methodical about this. You really only have:

Fuel
Exhaust
Transmission
Bearers
Electrics and
Throttle/gear cables.

to worry about. When the engine is out - it is an excellent time to consider renewal/replacement of skin fittings or difficult to get to bits which are so much easier to get to.

When the time comes to actually lift the engine out - have someone in the boat checking all is free. It's amazing how many bits attache to the engine!

Good luck

Donald
 
Make sure you disconnect everything (electric, fuel, water, propshaft, throttle, gear cables) from the engine before trying to move it. With a small engine like yours you may not need to split the gearbox from the engine itself but it might make things easier as two smaller lighter packages so to speak. On similar grounds detaching the alternator and the starter might be worth considering.
Think about how you are going to get it out, how the weight will be dealt with, what obstructions are in the path etc etc
 
I replaced a Stuart with a Yanmar 1GM on my Stella a few years ago, so have done this job in reverse.
If your cockpit floor is removable it makes disconnections so much simpler. Otherwise think about forming a hatchway.
Borrow, rent or buy a chain hoist and rig up a strong back with enough headroom to hoist clear of the coamings. If you'r in a shed, use the rafters otherwise rig up some scaffold tubes.
You will need to manhandle the lump forward onto cabin sole on wood blocks, but you can usually take much of the weight on the hoist.This will give you clearance to re-attach the hoist and it will go straight up through the hatch.
Have a few lengths of 4 x 2 ready to rest the engine on in case you have to reposition the hoist to traverse.
I tried to do this at first with a rope tackle but soon gave up & went for a chain hoist, so much easier.
It's not difficult, but think through each step in advance and take it slowly.
[Or buy yourself a surgical truss now]
Good luck.
Dan
 
Done this, but on my Folkdancer, month or so ago. Used 4X2 plus mainsheet to lift off mounts. After that it ended up with two of us ( combined age =120) heaving it in stages. Rope bridles around it gave us something to grab. I was a bit worried about weight on side decks tipping the whole shebang into the water but used a hefty plank to bridge from coaming to pontoon and we walked it ashore. Get it on the flat and two can carry but it's the awkward positions on the boat that require planning.
 
I agree that 2 people, given access, can easily manhandle a 1GM10 around. I've made this discovery as I'm in the middle of installing one. It is possible to lift the Yanmar a small distance, in my case on and off mounts, on your own if a reasonably hefty individual as it weighs in at around 70 Kg which is not all that heavy. Probably not advisable though if you ask the health and saftey wallahs. In comparison a 2 cylinder Stuart Turner weighs about 112 KG before you start taking bits off it.
At the moment the boat is on the hard and to get the Yanmar on board we had two men and a ladder lifting the engine off the ground to deck level and two of us in the boat to lift it inboard. It was then not very difficult for the two on board to heft it down into the cabin. Much easier if you have the boom rigged, which I didn't, so you can sling a tackle on to the boom.
 
thanks for all the advice. The boat is still in the water (in a mud berth marina) and although I intend on lifting her out, I thought I might take the engine out whilst she's low enough to make it easier i.e no need for ladders. I'm surprised to hear the engine is manageable to lift for 2 people - are you managing this with the gearbox attached? I was going to pay the yard to lift it out with the crane!!
 
Whatever you choice of method, are you sure extraction is really called for. I know the engine space on the Stella is pretty tight but the cylinder should be reasonably accessible. Compression problems on a diesel are surely all at the top end. I would be tempted to remove only the cylinder head, or if the rings are shot (easy to test with a little light oil and a compression guage) maybe the cylinder barrel BUT LEAVE THE ENGINE WHERE IT IS.
 
Yes indeed.
I know nothing detailed about these engines, but if you can remove the head and the barrel, you could presumably get the piston out too if needed by removing the gudgeon pin.

Sounds like an 'in situ' job to me.

Ron
 
Well, the old boy that's going to help me (as I'm far from a mechanic) has a workshop close by and I don't think he wants to be on his knees in the cold on an old boat. Also, with it out I'll get to learn all the tricks and improve my knowledge!

Thanks for all the help. I'll keep you posted on progress
 
You can remove the head in situ but no chance the barrel as it dosent come off ..ie part of crankcase...pity also you have to strip the complete engine!..for rebore .maybe its just valves need attention then your lucky!
In fact if its just the valves all you have to do is take the head off...easy
so test with oil first!
 
If you take the engine out while still in the water you may have a problem with water coming in via the prop shaft gland.
It can be lifted by 2 people (better with 3) , I replaced mine with a Nanni 14 (about the same weight) by having a scaffold tower at the back of the boat and carried the engine both down and the new one up.
 
For the record the engine is not a major issue and the cylinder head is very often a cause of the compression. The cylinder bore will need close inspection though as they have a major tendancy to "Glase Up". To remove a piston from a 1gm you WILL NOT do this in situ, you might remove the engine from the mounts and have the engine in your cabin but the engine will be very sick all over the place, as it almost always is in a workshop let alone inside a boat.
I can lift a 1gm 10 by myself and would recomed removing the gear box if that is your intenshion to lift. If you want to lift the engine go side on and use the engine feet as they are solid and good to hold onto. use plently of carpet or dust sheets for protection to all wooden surfaces. and other than that good luck.

P.s. I'm a Yanmar Trained engineer for 8 years ! and have installed many.
 
I replaced my 1GM with a 1GM10 a couple of years ago using the boom as a hoist, and with some pre planning and some help from freinds, had the old engine on the dock and the new engine resting on the mounts in less than 15 minutes. The problem I have is that my 1GM with very few hours on it but needs a new oversize 72.25mm piston because of pitting in the block and Yanmar does not have oversize pistons for the GM series anymore making the engine un rebuildable. If I had known this at the time I think I would re-engined with another brand I can't beleive that any engine manufacrue would stop producing a part for a marine engine as basic a piston no matter how old the engine is, and my 1GM was made in 1982 not that old by marine engine standards.

Richard Browning
Southern California
 
[quote
I can lift a 1gm 10 by myself

[/ QUOTE ]

Good grief! I can hear the Health and Safety bods rumbling from here!

If you are young and fit, and know how to lift a heavy weight safely, and if your back is 100%A1 Lloyds, then yes.

Otherwise you are risking a lifetime of the misery of back pain. Not nice.
 
thanks for all the help. An update is that I've managed to remove everything and that the engine awaits being lifted out. It all seemed very easy although I'm guessing it won't be quite as straight forward putting it back in! My mate didn't manage to get down to the boat and so we haven't lifted it yet
 
Just to add a little more. I have lifted my 1 GM three times now with all the bits on using the main sheet and a 4x2 across the hatch. The lifting ring gives a good balance. Don't take the gearbox off unless absolutely necessary for access. While you have it out suggest you overhaul the water pump and inspect/replace the external oil feed pipes as these are a pain to do in situ. Also clean the water jacket as far as possible and the rubber hose that bypasses the thermosat as these bung up.

I brought mine home and it is so much easier to work on it on a wood cradle on a work mate!

Good luck
 
[ QUOTE ]
I would be surprised if there are no after market pistons available at the size you want. They don't have to be made by Yanmar.

[/ QUOTE ]

any help locating one would be very much aprecated I have been looking for two years with no luck

Richard
 
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