sidneyp
New member
can anyone advise me!! i have a 4.3 mercruiser engine and have not used it for 12 months. i have tried to turn it over and have found it siezed. does anyone have any suggestions!!!!!!!!!!!!!!!!
engine stuck
- Thread starter sidneyp
- Start date
Its_Only_Money
New member
I'd guess you've got a ring or two rusted to the bores, if you take the heads off you'll be able to get some wd40 to them (you'll have to assume all may be stuck I guess as none will move), and maybe get them unstuck. Trouble is you won't know if any rings break - and if you do break a ring it'll pickup on the bore when you run it.
Only way to be sure is engine out and strip it (heads and sump off only, that will let you tap out any stuck pistons and rings, replace any broken rings (if you can get std size rings alone, if not you need a piston/rings set), and put her back together - will cost you gaskets and labour but anything else risks costing you for rebore + pistons on top of that +greater degree of stripdown (and if only 1 ring breaks you'll have to rebore and replace all 6 pistons to retain balance).
Not good, any shortcuts depend on how much trust you want to have in the unit afterwards and a bit of a gamble on costs.
Good luck!!
Only way to be sure is engine out and strip it (heads and sump off only, that will let you tap out any stuck pistons and rings, replace any broken rings (if you can get std size rings alone, if not you need a piston/rings set), and put her back together - will cost you gaskets and labour but anything else risks costing you for rebore + pistons on top of that +greater degree of stripdown (and if only 1 ring breaks you'll have to rebore and replace all 6 pistons to retain balance).
Not good, any shortcuts depend on how much trust you want to have in the unit afterwards and a bit of a gamble on costs.
Good luck!!
stamfordian
New member
B efore anyhing take plugs out and squirt wd40 into each bore then try to turn engine by hand....with a spanner VERY gingerly,this wll prove it,s actually siezed and is not anyhing else like siezed bendix on starter motor or indeed a duff battery? 12months dosn,t seem long enough for rings to rust onto bores but if they are do as othes have said
Freebee
Well-known member
I agree, dont remove the heads yet, just take plugs out and squirt wd40 or diesel in the bores, if possible leave to soak overnight , then put a spanner on crankshaft nut and turn it over-in neutral of course. Dont beat the hammer if the engine wont move, but you could use a piece of tubing over the shank of the spanner to increase leverage. Hope fully things will free up to turn over with the spanner on its own , then before putting the plugs in turn it over with the starter having put some rag over the plug oles to catch the diesel or wd as it sprays out,having made sure that exposed plug leads cannot create a stray spark. Now is a good time to clean up regap or renew the plugs!
Replace plugs and try to start it. having made sure that exposed plug leads cannot create a stray spark.
Dont forget to mark the plugs leads before you remove them from the plugs!
Replace plugs and try to start it. having made sure that exposed plug leads cannot create a stray spark.
Dont forget to mark the plugs leads before you remove them from the plugs!
enterprise
New member
Agree with all so far, the only addition would be to use 2 stroke oil, the sort you premix for outboards.
This will burn off once the engine starts.
If you manage to get it rotating by hand, before replacing the plugs compression check the bores.
If your engine has suffered a hydrolock through water entering a bore when you turn it over water will come from the holes for the plugs.
Obviously you will need to do more if this is the case.
Was the engine winterised?
Hope all works out fine.
This will burn off once the engine starts.
If you manage to get it rotating by hand, before replacing the plugs compression check the bores.
If your engine has suffered a hydrolock through water entering a bore when you turn it over water will come from the holes for the plugs.
Obviously you will need to do more if this is the case.
Was the engine winterised?
Hope all works out fine.
oldgit
Well-known member
Not an uncommon problem with petrols.
Only comment to add is make sure you put a decent quantity of penetrating oil in the bores.As bores are lying at angle need to cover whole of piston crown.Personally would leave for at least 24 hours.If only little ring of rust holding pistons,after soaking engine should turn over fairly easy with decent spanner on crank bolt.Have released several seized lumps this way including 2 x 120 HP Mercruisers that had not turned for at least 3 years.Once free turn over lots of times on starter to get oil all round engine before popping those plugs back in.You find you will have to clean them(the plugs) a few times before she will run proper due to wetting plugs with oil.Also know of a diesel unit got going after 6 weeks at the bottom of a dock.Best bit is clouds of smoke engulfing boatyard we she does start.Ps.dont forget to put the leg in a barrel of water etc or you will trash the impeelors.Good luck.
Only comment to add is make sure you put a decent quantity of penetrating oil in the bores.As bores are lying at angle need to cover whole of piston crown.Personally would leave for at least 24 hours.If only little ring of rust holding pistons,after soaking engine should turn over fairly easy with decent spanner on crank bolt.Have released several seized lumps this way including 2 x 120 HP Mercruisers that had not turned for at least 3 years.Once free turn over lots of times on starter to get oil all round engine before popping those plugs back in.You find you will have to clean them(the plugs) a few times before she will run proper due to wetting plugs with oil.Also know of a diesel unit got going after 6 weeks at the bottom of a dock.Best bit is clouds of smoke engulfing boatyard we she does start.Ps.dont forget to put the leg in a barrel of water etc or you will trash the impeelors.Good luck.
robind
New member
Re: Not an uncommon problem with petrols.
If in doubt use warm/hot oil (into the plug holes) sae 30 ish with a little parafin mixed in it and leave for a while before turning with a spanner. You will think that you have a Volvo when she finally starts up from the smoke (I suggest you do it at night. ;o))) )
Best of luck
Rob
If in doubt use warm/hot oil (into the plug holes) sae 30 ish with a little parafin mixed in it and leave for a while before turning with a spanner. You will think that you have a Volvo when she finally starts up from the smoke (I suggest you do it at night. ;o))) )
Best of luck
Rob
sixpack
N/A
[ QUOTE ]
(and if only 1 ring breaks you'll have to rebore and replace all 6 pistons to retain balance).
[/ QUOTE ] Bollocks!
One jambed / broken ring with damaged bore means one rebore, sleeve and rebore back to original bore. NOT 6 rebores and new pistons. Odds are original piston can be salvaged so only a set of rings needed.
(and if only 1 ring breaks you'll have to rebore and replace all 6 pistons to retain balance).
[/ QUOTE ] Bollocks!
One jambed / broken ring with damaged bore means one rebore, sleeve and rebore back to original bore. NOT 6 rebores and new pistons. Odds are original piston can be salvaged so only a set of rings needed.
Solitaire
Active member
I take it you don't agree then!! /forums/images/graemlins/crazy.gif
whisper
New member
I can't add to the suggestions, but welcome to the forum sydneyp. I hope that your future posts will concern more cheerful subjects. Good luck.
lanason
Active member
I think your right !! he doesnt agree, but I have just looked up the meaning of "bollocks" in my engineering apprenticeship course book. It says "a techincal term used to desciribe a piece of mechicanical equipement that it non-functional, as in boll'oxed.
Mind you running an engine with single bolloxed ring would bollox the bearing, put an uneven load on the crank, wear the other 5 bearings causing them to become bolloxed, and then damage the other 6 bores, maybe even breaking a conrod, sending the piston out of the top of the engine through the side of the boat and causing the boat to sink, raising the waterlevel in the marina, flooding the toilet block, releasing raw sewage into the river and polluting the whole of mankind.
so I think there are both wrong /forums/images/graemlins/wink.gif
Mind you running an engine with single bolloxed ring would bollox the bearing, put an uneven load on the crank, wear the other 5 bearings causing them to become bolloxed, and then damage the other 6 bores, maybe even breaking a conrod, sending the piston out of the top of the engine through the side of the boat and causing the boat to sink, raising the waterlevel in the marina, flooding the toilet block, releasing raw sewage into the river and polluting the whole of mankind.
so I think there are both wrong /forums/images/graemlins/wink.gif
truebrit
New member
A plant engineer friend , always reckoned "redex" was the stuff to squirt in to free seized engines
LittleShip
New member
Iv'e used diesel oil to free stuck pistons(rings) not great when you start up but it does work. Remove plugs pour in th ediesel leave it for a few days to do its job then try turning from the crank not the starter motor.
Next time you are going to leave your engine for a lenghth of time, remove plugs add some oil, turn over engine by hand and replace plugs. I have been doing this with classic cars for years never had any problems.
Next time you are going to leave your engine for a lenghth of time, remove plugs add some oil, turn over engine by hand and replace plugs. I have been doing this with classic cars for years never had any problems.
oldgit
Well-known member
Redex just the job.
But have you tried to buy any recently.............
But have you tried to buy any recently.............
Vara
Active member
B
bob_tyler
Guest
Re: Redex just the job.
Any good car accessory shop.
Any good car accessory shop.
Its_Only_Money
New member
Had long post here about how my experience obviously different to sixpacks but can't be bothered to get that involved anymore, have decided to try out the ignore feature instead.
cliff
Active member
[ QUOTE ]
can anyone advise me!! i have a 4.3 mercruiser engine and have not used it for 12 months. i have tried to turn it over and have found it siezed. does anyone have any suggestions!!!!!!!!!!!!!!!!
[/ QUOTE ] Lots of advice above. First question is how many pistons are seized? to find out you could try lifting the heads and check for movement at the crown of each piston. If this check is inconclusive drop the sump and undo the big end bearings and carefully tap each piston upwards in turn until you find the stuck piston(s).
Now is decision time as to the cure....Lusol or PlusGas or Redex down the offending bore and leave to soak for a few hours/days and see if you can get the stuck piston(s) moving, reassemble and sell the boat before the engine packs in again OR remove the heads and remove the stuck piston(s) to allow you to check the bore for damage be it scratches or ovality from broken rings or corrosion pitting from the piston being corroded in place. If there is any mechanical or corrosion damage this will need rectifying possibly by lightly honing the bore or a rebore or a bore and sleeve bringing the bore back to original size.
If only one bore is damaged then the bore, sleeve and rebore back to original (as advocated by sixpack) would be cost effective provided the remaining bores are O.K. I have used this method on many occasions to salvage an engine without the costs of fully reboring and procuring a full set of oversize pistons.
If the piston(s) are O.K. then all that would be needed is a set of rings and a gallon or two of running in oil to help the new rings bed into the new liner quickly. If the engine is generally "shagged" then you might decide to bite the bullet and go for a full rebuild (ouch!).
Before you decide which way to go I would suggest you check on the price and availability of oversize pistons and rings and the cost of a full rebore.
There are many ways of "fixing" your problem, some more permanent" than others and some extremely expensive.
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can anyone advise me!! i have a 4.3 mercruiser engine and have not used it for 12 months. i have tried to turn it over and have found it siezed. does anyone have any suggestions!!!!!!!!!!!!!!!!
[/ QUOTE ] Lots of advice above. First question is how many pistons are seized? to find out you could try lifting the heads and check for movement at the crown of each piston. If this check is inconclusive drop the sump and undo the big end bearings and carefully tap each piston upwards in turn until you find the stuck piston(s).
Now is decision time as to the cure....Lusol or PlusGas or Redex down the offending bore and leave to soak for a few hours/days and see if you can get the stuck piston(s) moving, reassemble and sell the boat before the engine packs in again OR remove the heads and remove the stuck piston(s) to allow you to check the bore for damage be it scratches or ovality from broken rings or corrosion pitting from the piston being corroded in place. If there is any mechanical or corrosion damage this will need rectifying possibly by lightly honing the bore or a rebore or a bore and sleeve bringing the bore back to original size.
If only one bore is damaged then the bore, sleeve and rebore back to original (as advocated by sixpack) would be cost effective provided the remaining bores are O.K. I have used this method on many occasions to salvage an engine without the costs of fully reboring and procuring a full set of oversize pistons.
If the piston(s) are O.K. then all that would be needed is a set of rings and a gallon or two of running in oil to help the new rings bed into the new liner quickly. If the engine is generally "shagged" then you might decide to bite the bullet and go for a full rebuild (ouch!).
Before you decide which way to go I would suggest you check on the price and availability of oversize pistons and rings and the cost of a full rebore.
There are many ways of "fixing" your problem, some more permanent" than others and some extremely expensive.
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cliff
Active member
[ QUOTE ]
[ QUOTE ]
(and if only 1 ring breaks you'll have to rebore and replace all 6 pistons to retain balance).
[/ QUOTE ] Bollocks!
One jambed / broken ring with damaged bore means one rebore, sleeve and rebore back to original bore. NOT 6 rebores and new pistons. Odds are original piston can be salvaged so only a set of rings needed.
[/ QUOTE ] Totally agree with you sixpack. Seems we have two different schools of thought on this one but I must admit I am in favour of the bore/sleeve/rebore to original method is only one (or even two) pots are seized having successfully done the same on many occasions to keep costs down.
------
[ QUOTE ]
(and if only 1 ring breaks you'll have to rebore and replace all 6 pistons to retain balance).
[/ QUOTE ] Bollocks!
One jambed / broken ring with damaged bore means one rebore, sleeve and rebore back to original bore. NOT 6 rebores and new pistons. Odds are original piston can be salvaged so only a set of rings needed.
[/ QUOTE ] Totally agree with you sixpack. Seems we have two different schools of thought on this one but I must admit I am in favour of the bore/sleeve/rebore to original method is only one (or even two) pots are seized having successfully done the same on many occasions to keep costs down.
------
cliff
Active member
[ QUOTE ]
Had long post here about how my experience obviously different to sixpacks but can't be bothered to get that involved anymore, have decided to try out the ignore feature instead.
[/ QUOTE ]
If you ignore everyone who disagrees with you, you must be quite a lonely person. Sad really as it is the differences that make things interesting.
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Had long post here about how my experience obviously different to sixpacks but can't be bothered to get that involved anymore, have decided to try out the ignore feature instead.
[/ QUOTE ]
If you ignore everyone who disagrees with you, you must be quite a lonely person. Sad really as it is the differences that make things interesting.
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