Yanmar 3GM30 only does 3/4 turn

Val V

.
May 8, 2013
20
Canadian Sailcraft 33 Perth Amboy, NJ
This winter I took on two small projects to help replace the oil going forward on my 3GM30F engine (circa 2000). I removed the oil pan, drilled and tapped the bottom to help drain the oil. Second thing I did was installed remote oil filter relocation kit. Engine ran great last time i used it 2 months ago.

After re-assembly with new gasket and refilling the oil I tried to turn it over by hand. released pressure from all three cylinders and tried to turn. it only turns 3/4 of a turn and then sounds as if its hitting something (dull knock sound). The 3/4 turn that it does turn go nice and smooth but not beyond that either direction. I am 100% certain my newly installed drain plug is not protruding the inside of the pan and it is impossible for the rods or anything to hit it. Has to be something else. Cant wrap my brain around this....

Any thoughts?
 

Attachments

May 27, 2004
1,964
Hunter 30_74-83 Ponce Inlet FL
A very clean installation which I cannot see causing the problem.
But, someone here will have a theory or hypothesis or a witty comment.
no doubt!
Hold on a minute. Is there a possibility that some shavings from your tap job
migrated from the pan to a connecting rod.
( See, I told you someone would have a theory. ) :biggrin:
 
Last edited:

Val V

.
May 8, 2013
20
Canadian Sailcraft 33 Perth Amboy, NJ
:) Not a chance. All work on the pan was done in my shop. It was so clean I could eat off of it.
 
Jan 7, 2014
395
Beneteau 45F5 51551 Port Jefferson
Is the boat in gear? Can you hear where the thump is coming from? Could the kit be interfering with the oil pump?
 
  • Like
Likes: mz4wheeler
Oct 1, 2007
1,856
Boston Whaler Super Sport Pt. Judith
Could the thump be external to the engine? Something like a tool fouling a rotating element like the alternator?
 

Val V

.
May 8, 2013
20
Canadian Sailcraft 33 Perth Amboy, NJ
Is the boat in gear? Can you hear where the thump is coming from? Could the kit be interfering with the oil pump?
I dont see how but I will remove and check without it.
Not in gear. Tried both ways
 

RoyS

.
Jun 3, 2012
1,739
Hunter 33 Steamboat Wharf, Hull, MA
I am assuming that you performed this job with the engine in the boat. I salute you for that. Is it possible that while wrestling the pan out from under and back in that you disturbed the oil pick-up assembly? Just suggesting possibilities here.
 
  • Like
Likes: ggrizzard

Val V

.
May 8, 2013
20
Canadian Sailcraft 33 Perth Amboy, NJ
I am assuming that you performed this job with the engine in the boat. I salute you for that. Is it possible that while wrestling the pan out from under and back in that you disturbed the oil pick-up assembly? Just suggesting possibilities here.
Thanks. Yes I was able to do the whole thing without removing the engine. In my case there is enough room my both hands to reach all bolts if laying flat on the floor. Anyway, I also thought about the oil pickup and it's a possibility but its hard to imagine it would be SOOO out of place that it would get in the way of the rods. Trying to avoid removing the oil pan again :)
 
Nov 6, 2006
9,885
Hunter 34 Mandeville Louisiana
I understand that you ran it after the mods. If so, this problem should not be related to the stuff you did. Is there a bunch of water in the crankcase? Did it possibly ingest something that is stuck on top of one piston? (Air cleaner on and in good shape?) something like a 12 mm nut stuck on a piston top could do that, I think.
With the compression releases engaged, and functional, not possible to water lock it from the top end. A puzzle indeed; please let us know what ya find.
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
I know you were working on your oil system, but is there any chance you may have removed/replaced your fuel lift pump as well and forgotten to mention this ?

I know that the symptom which you describe can be the result of inserting the cam rider off to the side of its cam. If it's in a tight location, you'll never know it. It's the only reason I mention this slim 1:1,000,000 chance.

Your working photos show you know exactly what you're doing, now it's just a matter of systematically examining what you did that's jamming the engine.

PS Looking back at Kloudie's remark about running the engine, is it correct to say that you DID NOT run the engine after the oil mods but only turned it by hand and found the sticking point ?
 
  • Like
Likes: ggrizzard
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
Still looking for obscure causes ?

You would have had to remove the oil originally (before the mods), by using a vacuum pump through the dip stick hole. Any chance you unknowingly broke off the end of the plastic tube and it's now causing interference ?

Desperate times call for desperate suggestions :banghead:.
 

Val V

.
May 8, 2013
20
Canadian Sailcraft 33 Perth Amboy, NJ
I know you were working on your oil system, but is there any chance you may have removed/replaced your fuel lift pump as well and forgotten to mention this ?

I know that the symptom which you describe can be the result of inserting the cam rider off to the side of its cam. If it's in a tight location, you'll never know it. It's the only reason I mention this slim 1:1,000,000 chance.

Your working photos show you know exactly what you're doing, now it's just a matter of systematically examining what you did that's jamming the engine.

PS Looking back at Kloudie's remark about running the engine, is it correct to say that you DID NOT run the engine after the oil mods but only turned it by hand and found the sticking point ?
Thanks. No, I didnt touch anything in the fuel system at all and didnt need to. The fuel lift pump wasnt in the way of this project.
Correct. I did not start the engine and only tried it by hand.
 
  • Like
Likes: kloudie1
Oct 1, 2007
1,856
Boston Whaler Super Sport Pt. Judith
All belts were off and not in gear. :(
My last guess is this. Since you removed the belts you had to remove the plastic shroud on the front of the engine. Could something be fouled behind the cover? I'm just having a lot of trouble seeing this as an interference inside the engine from the way you described the care you took in the work.
 

Val V

.
May 8, 2013
20
Canadian Sailcraft 33 Perth Amboy, NJ
Still looking for obscure causes ?

You would have had to remove the oil originally (before the mods), by using a vacuum pump through the dip stick hole. Any chance you unknowingly broke off the end of the plastic tube and it's now causing interference ?

Desperate times call for desperate suggestions :banghead:.
Interesting theory actually. Unfortunately this is not the case here because it didnt break off. While I was painstakingly scraping off old gasket I used my cellphone camera to take pictures from under the engine to see how I am doing on my progress. I took a lot of pictures most of them pointing to the rim of the engine block but there were also many showing exposed rods, etc. There were no foreign objects.

The problem I had for years with this engine model is the fact the dipstick end points directly at the top of the oil suction cup approximately in the center of the oil pan. I never had good luck with those vacuum oil extractor plastic 1/4 tubes. They always hit that oil pickup and dont go all the way down the pan. It so happens that all the oil changes are done early November as part of winterization and the cold weather makes that plastic tube not flexible at all.
 

Val V

.
May 8, 2013
20
Canadian Sailcraft 33 Perth Amboy, NJ
My last guess is this. Since you removed the belts you had to remove the plastic shroud on the front of the engine. Could something be fouled behind the cover? I'm just having a lot of trouble seeing this as an interference inside the engine from the way you described the care you took in the work.
My engine never had that plastic cover.
 
Jun 2, 2011
347
Hunter H33 Port Credit Harbour, ON.
It sounds to me like there should be nothing mechanical in the bottom end causing the problem and nothing in the top end either. I don't know if this is possible and I have never seen this happen but you could have a fuel line partially charged and as you turn the engine by hand the fuel pump could possibly be locking up with the rotational force that you are trying. With the decompression levers engaged the fuel system will still fire the injectors as you rotate the crank. Maybe you are not exerting enough rotational force to fire the injector. Try to release the injector nuts at the injectors or at the fuel pump to release any built up pressure and try and rotate the engine again.

Good luck.