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yanmar 3 cly. blowby

bmckenzie

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Joined
Nov 25, 2013
Messages
76
Location
northern california
Occupation
self employed
Hi all,
Can any one out there tell me how much blow by is acceptable ? Mine has 1800 hours and when I take off valve cover oil cap ( after full warm up, maybe running 30 minutes) their is quiet a large amount of vapor / blowby and also when it is running and I pull the dipstick it blows oil out the dipstick hole along with oil vapor. Are the rings shot or do all these yanmar 3 cly have a lot of crankcase pressure??
 

mjpetersen

Member
Joined
Jan 27, 2010
Messages
20
Location
Poland
Occupation
missionary independent baptist
I have 2 yanmar 3 cylinder engines, one in a small tractor and a second in a B17/2 mini ex. Neither one has any crank case pressure. there should be a vent pipe on the valve cover that vents to the atmosphere, I suspect that vent is plugged or kinked so that the natural pressure in the case cannot escape properly. That is not to say that your engine is not badly worn, but at 1800 hours I doubt it. My mini-ex has close to 4800 and it started life as a rental.
Mike
 

AirBornOne

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Joined
Oct 17, 2008
Messages
146
Location
S.F.Bay Area
Doesn't sound good bmckenzie,
Crankcase pressurization means leaking cylinder pressure and is usually present to a small degree.This sounds like too much.
A compression test (more correctly a leakdown test) will tell you more about the pressure you see blowing by.
Cracked piston(s),worn rings,blown head gasket are the usual suspects.
Then it could be as simple as Mike says,a pcv valve or line could be plugged (critters?) or kinked.Have you done any maint. work lately? Maybe a vented oil filler cap is meant to be fitted.
Hoping for the best
J
 

bmckenzie

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Nov 25, 2013
Messages
76
Location
northern california
Occupation
self employed
thank you both for the replies, I am going to have the local equipment mechanic have a look at it. I bought the machine with a 30 day make it right warranty and it will be up in a week or so . If there is something wrong maybe I can have them repair it.
 

yanmarman

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Jul 5, 2011
Messages
112
Location
Pa.
Occupation
union ironworker
Sounds like motor is shot,maybe to much starting fluid
 

bmckenzie

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Joined
Nov 25, 2013
Messages
76
Location
northern california
Occupation
self employed
well, the bad news is that something is wrong, the good news is that the company I bought it from with the 30 day warranty had my excavator picked up by the local john deere dealer to have the motor gone through. I have to put the work on hold I had planned for it but at least it will be fixed. I will keep everyone informed on what the problem was after they get it torn down. thanks again for the replies.
 

bmckenzie

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Joined
Nov 25, 2013
Messages
76
Location
northern california
Occupation
self employed
yes , they have it torn down and had taken it to the machine shop to see what the scoop was. At some point the engine had gotten dusted out, the cylinders had too much taper to ring, so now it is 1- find over size pistons and bore, 2- install sleeves and std. pistons, 3- new short block, 4- new engine. I think they ruled out a new engine after the got a price from takeuchi :). The shop has 3 tractors down needing rebuilds so I think I am a ways down the list but I wish something would start happening, I have a demo project waiting on this. Will have more info towards end of the week.
 

AirBornOne

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Joined
Oct 17, 2008
Messages
146
Location
S.F.Bay Area
yes , they have it torn down and had taken it to the machine shop to see what the scoop was. At some point the engine had gotten dusted out, the cylinders had too much taper to ring, so now it is 1- find over size pistons and bore, 2- install sleeves and std. pistons, 3- new short block, 4- new engine. I think they ruled out a new engine after the got a price from takeuchi :). The shop has 3 tractors down needing rebuilds so I think I am a ways down the list but I wish something would start happening, I have a demo project waiting on this. Will have more info towards end of the week.
I've discovered that Yanmar diesel engines are very popular in boating circles (though that hasn't helped me sourcing a coolant temp sensor :( ).
I'm thinking why bother with Takeuchi?
After a quick Google search there appears to be more Yanmar support in marine applications than heavy equipment.
I think I would vote for oversize pistons/rings,what little extra power may result is sure to be appreciated.IIRC these little .75l diesels are rated @ appx. 12-13HP.
HTH
J
 

bmckenzie

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Nov 25, 2013
Messages
76
Location
northern california
Occupation
self employed
yes, yanmar is very popular in the marine industry. It seems to be used by many equipment manufactures also, which is why my rig went to the john deere dealer as thy use a lot of yanmar in their compact equipment line. I think in my case it comes down to what the bean counters will ok. This is a 3tnv series that is used in a lot of applications so it is not the parts availability , it's the money part. I wish I did have a vote here but its between the insurance co and the john deere dealer
 

ValleyFirewood

Senior Member
Joined
Aug 17, 2013
Messages
311
Location
Palmer, AK
What is the excavator that uses such a small engine? I'm just curious.

Hard to believe a 10ish hp motor would be expensive to where machine it would be worth it... Almost would think it to be a "throw away" engine.
 

AirBornOne

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Oct 17, 2008
Messages
146
Location
S.F.Bay Area
What is the excavator that uses such a small engine? I'm just curious.

Hard to believe a 10ish hp motor would be expensive to where machine it would be worth it... Almost would think it to be a "throw away" engine.
The mini I was referring to is a 3500# TB-016 Takeuchi with the 750cc 3 cyl. Yanmar. I didn't think a 3cyl. engine would be used on anything larger.Doh :eek:

bmckenzie said:
I wish I did have a vote here but its between the insurance co and the john deere dealer .
Well that sure beats paying out of pocket!
yes, yanmar is very popular in the marine industry. It seems to be used by many equipment manufactures also, which is why my rig went to the john deere dealer as thy use a lot of yanmar in their compact equipment line.
I had no idea John Deere was using Yanmar,maybe I can get a temp sensor afterall.
Hoping the best.
J
 

ValleyFirewood

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Aug 17, 2013
Messages
311
Location
Palmer, AK
I believe it produces around 28 h.p. , it is in a takeuchi tb-135 , about an 8000 lb machine

Good machine, I used one this summer to dig a 20ish ft deep hole. Great on fuel too, under a gal an hr.
I didn't realize it was just a 3 cylinder, I'd never have guessed. It was a rental so I never really looked.
 

ValleyFirewood

Senior Member
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Aug 17, 2013
Messages
311
Location
Palmer, AK
The mini I was referring to is a 3500# TB-016 Takeuchi with the 750cc 3 cyl. Yanmar. I didn't think a 3cyl. engine would be used on anything largeYanmar,maybe I can get a temp sensor afterall.
Hoping the best.
J

Yanmar engines have been used in John Deeres for over 30 years.
 

dozier man

Member
Joined
Jan 14, 2014
Messages
20
Location
north ga
i have a tbo35 takeuchi same problem your having lots of blow by and smoking and hard to start when cold it has 2900 hrs ive been looking for a rebuild kit for the engine with no luck
 

bmckenzie

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Nov 25, 2013
Messages
76
Location
northern california
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self employed
If your engine is shot ( rings, cly. wear, valves) your local engine machine shop can order all parts needed along with gasket sets
 

yanmarman

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Jul 5, 2011
Messages
112
Location
Pa.
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union ironworker
Dominion Equipment men for parts in Va. phone number877-828-7785. I don't ever call yanmar for parts olny Dominion.hope this helps everyone out later Yanmarman
 

bmckenzie

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Joined
Nov 25, 2013
Messages
76
Location
northern california
Occupation
self employed
Up date, I got my mini back late yesterday afternoon from the local Deere dealer. New water pump, pistons, valves , valve guides, bored and sleeved, bearings .I believe it was worth the wait. I ran it about an hour last night and it purrs like a fine Japanese watch! . On with the demo project. Maybe a picture later if I can figure out how to post.
 
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