Yanmar 4JH4E Injection Pump

[Charlie]

I have been having an off and on problem with my engine diluting the lubrication oil with diesel. I thought it was the lift pump and replaced that. It stopped. Then it started up again. I bypassed the lift pump and installed an electric lift pump. It stopped. The boat sat on the hard for four months. I replaced the injectors. The engine ran very well. After an hour it started to smoke. There was diesel sitting in the injector holes and when I removed the oil it had added 4 quarts of fluid to my lubricating oil.

With the help of Del I decided that my best plan was to empty the excess oil. Replace it with new oil. Then sail back to the berth. I sailed as much as I could but the tide was turning and the wind died to nothing. I ended up motoring back at a slow speed, it took me about an hour. I checked the oil when I got to the dock and there was some but not a lot of excess liquid.

I spoke to the diesel injection shop. Bring us the the injector and the injection pump. You have two different problems 1) the injectors we rebuilt leak and 2) the injector pump or the lift pump is leaking.

Injectors came out easy. Injection Pump not so easy. The manual wasn't very helpful. It wanted me to mark the idler gear and the injection pump gear so that I could reinstall the IP in the same location. There is no way to do that without taking off the front of the engine. After searching the internet and calling a bunch of people and asking mechanics I was still had no answer.

Finally I spoke with the injection shop and while they didn't have any specific Yanmar info they told me what I needed to know ( I hope!).

1) Set the engine to TDC on the compression stroke.

2) mark the engine block and the injector pump with a center punch so that you will not have to retime the injection pump.

3) Remove the injection pump.

Okay #3 needs some more info.

a) Remove all hoses and wires from the IP.

b) If you can remove the lift pump.

c) Remove the stop solenoid

d) Remove the oil overflow pipe. This was difficult. I could not get to the 17mm bolt with a socket. a 17mm stubby would have been nice. I ended up using a 17mm wrench of normal size but had to hit it with a hammer to "break" the nut.

e) With the oil overflow removed I was able to get a 6" and a 3" extension along with a 12 point 12 mm deep well socket underneath and behind the IP and attach it to the nut. I recommend using a 6 point socket. I rounded it with my 12 point. Luckily I had my rounded bolt removal tool Irwin Bolt Grip 5pc Base Set 394001 by Irwin Industrial Tool Inc. for $33.99 - America's Farm and Home Store .

f) the other two bolts holding the IP were removed one with a wrench and one easily with the 9"s of extension.

g) The manual recommends using a gear puller to seperate the IP shaft from the IP gear. You are unable to do this unless you pull the front of the engine. I loosened the nut from the shaft and got out a 1/2" brass punch. I few strikes with this allowed the shaft free of the gear.

As an aside to find TDC on cylinder #1 on the compression stroke is easy. After researching it for a few hours. Hee hee hee.

1) There is an ~ 1.25" hole covered by a rubber plug on the flywheel case. Remove that and there are markings that tell you TDC for the engine. I had to use a mirror to figure out the markings. Then I double checked it by watching the IP and when the #1 cylinder squirted fuel I knew the engine was at TDC on the compression stroke. (Please correct me if this is wrong)

It took me about half a day to get this out. If I had had this information it would have been a two hour project given my reasonable access to the engine.

The diesel injection shop tested the IP. Ran it for a half hour with 65 lbs of pressure and it didn't leak. They were stumped. When they couldn't think of anything else they did it again and it leaked. Rebuild costs $1600 new pump $2600. Ouch!!!!

I'll let you know how it works out.

[Charlie]

Originally Posted by Charlie

I have been having an off and on problem with my engine diluting the lubrication oil with diesel. I thought it was the lift pump and replaced that. It stopped. Then it started up again. I bypassed the lift pump and installed an electric lift pump. It stopped. The boat sat on the hard for four months. I replaced the injectors. The engine ran very well. After an hour it started to smoke. There was diesel sitting in the injector holes and when I removed the oil it had added 4 quarts of fluid to my lubricating oil.

With the help of Del I decided that my best plan was to empty the excess oil. Replace it with new oil. Then sail back to the berth. I sailed as much as I could but the tide was turning and the wind died to nothing. I ended up motoring back at a slow speed, it took me about an hour. I checked the oil when I got to the dock and there was some but not a lot of excess liquid.

I spoke to the diesel injection shop. Bring us the the injector and the injection pump. You have two different problems 1) the injectors we rebuilt leak and 2) the injector pump or the lift pump is leaking.

Injectors came out easy. Injection Pump not so easy. The manual wasn't very helpful. It wanted me to mark the idler gear and the injection pump gear so that I could reinstall the IP in the same location. There is no way to do that without taking off the front of the engine. After searching the internet and calling a bunch of people and asking mechanics I was still had no answer.

Finally I spoke with the injection shop and while they didn't have any specific Yanmar info they told me what I needed to know ( I hope!).

1) Set the engine to TDC on the compression stroke.

2) mark the engine block and the injector pump with a center punch so that you will not have to retime the injection pump.

3) Remove the injection pump.

Okay #3 needs some more info.

a) Remove all hoses and wires from the IP.

b) If you can remove the lift pump.

c) Remove the stop solenoid

d) Remove the oil overflow pipe. This was difficult. I could not get to the 17mm bolt with a socket. a 17mm stubby would have been nice. I ended up using a 17mm wrench of normal size but had to hit it with a hammer to "break" the nut.

e) With the oil overflow removed I was able to get a 6" and a 3" extension along with a 12 point 12 mm deep well socket underneath and behind the IP and attach it to the nut. I recommend using a 6 point socket. I rounded it with my 12 point. Luckily I had my rounded bolt removal tool Irwin Bolt Grip 5pc Base Set 394001 by Irwin Industrial Tool Inc. for $33.99 - America's Farm and Home Store .

f) the other two bolts holding the IP were removed one with a wrench and one easily with the 9"s of extension.

g) The manual recommends using a gear puller to seperate the IP shaft from the IP gear. You are unable to do this unless you pull the front of the engine. I loosened the nut from the shaft and got out a 1/2" brass punch. I few strikes with this allowed the shaft free of the gear.

As an aside to find TDC on cylinder #1 on the compression stroke is easy. After researching it for a few hours. Hee hee hee.

1) There is an ~ 1.25" hole covered by a rubber plug on the flywheel case. Remove that and there are markings that tell you TDC for the engine. I had to use a mirror to figure out the markings. Then I double checked it by watching the IP and when the #1 cylinder squirted fuel I knew the engine was at TDC on the compression stroke. (Please correct me if this is wrong)

It took me about half a day to get this out. If I had had this information it would have been a two hour project given my reasonable access to the engine.

The diesel injection shop tested the IP. Ran it for a half hour with 65 lbs of pressure and it didn't leak. They were stumped. When they couldn't think of anything else they did it again and it leaked. Rebuild costs $1600 new pump $2600. Ouch!!!!

I'll let you know how it works out.

It took me about two hours to install including a trip to three different auto parts stores for crush washers. Finally found them at Ace Hardware. Ran the engine but I heard a loud POP. Rushed over studied the engine. Turned it by hand. Started it again it worked. Then I saw the diesel pumping out of the fuel filter. Everything worked well except that I had loosened the bleed screw. It went Pop and I couldn't find it. Back to hardware store for a temporary bolt to take the place of bleed screw. Ran for half hour no extra oil. Need a better test but that is a good start. While cleaning disel off the engine I found the bleed screw hiding under th e return lines. As Col. Hanibal from the A team would say "I love it when a plan comes together."

[delmarrey]

It sounds as though you had an intermittent problem with the pump. I hate it that happens I quit an electrics job because of that. It drives me nuts. I'll stick with mechanics.

Do you know which part of the IP that it was leaking?

Hopefully this will be the end of the problem!

[Soulflyer1980]

Hi Charlie, I am replying from my other thread to your input to my post. First of all thank you for your help!

Could you let me now, or have a link for the manual where it says anything about how to check if the lifting pump is spilling diesel into the engine oil? I have read your thread and it somehow seems that we have totally different IPs. I am pretty sure my IP is diesel lubricated and got no connection to the engine oil apart from an oil seal on the shaft of the IP. But the. A broken membrane can't spill diesel into the oil except if the oil seal at the shaft is damaged. That alone would spill diesel into your engine anyway.

Thanks

F


Sent from my iPad using Cruisers Sailing Forum

[Charlie]

Hi SF,

Here is a link to the discussion on the IP sending diesel thru the lubrication oil system. It also has a link to the test for the diaphragm pump and the manual as well. http://www.cruisersforum.com/forums/...p-66848-2.html