Yanmmar 4JH4-HTE 80HP 2007

[Compass790]

Bit alarming you ran into those problems on a 300 hr engine!
Did you try & get Yanmar to come to the party? If it was a problem from new it should have been their resposibility to rectify it.
Hope it's fixed for thousands of hours now.

[capitansurfista]

Originally Posted by Palarran

I have the same engines (2) and one did that. I'd check your fuel lines, supply, return, and vent.

Thank you Palarran, we of course have done that and our gen runs from same tank and fuel lines manifold etc...So it has to be a more tehc issue ....Love your cat type...Congrats...and Thanks again..

[Oceansailor]

Originally Posted by capitansurfista

Hi, have a weird problem with this engine since it was installed new!..It stalls or almost does when hot and in low rpm shifting gears fwd or rvse. OK when cold...We have check diesel , filters, everything...anybody out there whom may know about this problem? Appreciate the help. We are in Ecuador. Thank you so much for any good ideas to try fix this problem.

Had that problem on my Yanmar. Same model but 2008. After 400 hours it could be very hard (impossible) to start when warm. It did also stall in low rpm shifting situation.

It was a problem in the injection pump. Exactly what it was Yanmar never wanted to say. Got a new pump and it has been running 1500 hours, no problem.

[capitansurfista]

Originally Posted by Oceansailor

Had that problem on my Yanmar. Same model but 2008. After 400 hours it could be very hard (impossible) to start when warm. It did also stall in low rpm shifting situation.

It was a problem in the injection pump. Exactly what it was Yanmar never wanted to say. Got a new pump and it has been running 1500 hours, no problem.

tHANK YOU oCEAN SALIOR WE WILL TAKE AGAIN yANMAR TECH TO CHECK ON fUEL PUMP i GUESS...BUT YEAH THATS IS WHAT WE WILL NEED TO DO i THINK IS FAULTY CONTROLLER OF RPM tHANK YOU.

[capitansurfista]

Originally Posted by Compass790

Bit alarming you ran into those problems on a 300 hr engine!
Did you try & get Yanmar to come to the party? If it was a problem from new it should have been their resposibility to rectify it.
Hope it's fixed for thousands of hours now.

tHANK YOU cOMPASS i AM NEW CREW ON THIS bOAT, DONT KNOW EXACTLY WHY GARANTEE FROM YANMAR WAS NOT FIXED APPLIED ETC WILL FIND OUT SOON. tHANK YOU AGAIN FOR YOUR TIME

[capitansurfista]

Originally Posted by Oceansailor

Had that problem on my Yanmar. Same model but 2008. After 400 hours it could be very hard (impossible) to start when warm. It did also stall in low rpm shifting situation.

It was a problem in the injection pump. Exactly what it was Yanmar never wanted to say. Got a new pump and it has been running 1500 hours, no problem.

Ocean sailor the difference here is that starts and restarts no problem warm or cold works fine..problem is only when warm and trying to shift gears back or fwd..think is controller of rpm injection pump thank you..

[capitansurfista]

Originally Posted by Compass790

Bit alarming you ran into those problems on a 300 hr engine!
Did you try & get Yanmar to come to the party? If it was a problem from new it should have been their resposibility to rectify it.
Hope it's fixed for thousands of hours now.

I am not owner. I found out this engine was bought but never until 3 years as Boat under reconstruction. Dont know much details yet. Still I guess Yanmar should apply warranty as engine had zero hours...weird. Just trying to figure out things ...Thanks for your reply

[hpeer]

Timing? If yours is like mine it has a wax seal timing adjustment. Coolant flow through the fuel pump, warms the wax seal. Makes it easier to start sun cold and run cleaner when warm. Sorta.

You adjust the timing by rotating the fuel pum. 3 screws, one easy, one damn near impossible, one is impossible without removing an engine mount. (#%*%#^*+)

After replacing the fuel pump I had the opposite problem, engine would start flawlessly but would shut off when it warmed up. I was one tooth off on timing.

So if your timing is off even a little this MAY be the cause.

I would check the file pump to make sure it is rock solid in its mount, can not rotate. If so then just keep this in the back of your mind. If loose, bingo.

[capitansurfista]

I will have fuel pump and injection pump checked soon. Taking engne mounts to rotate that pump is crazy...cant do that very little access there so I will leave it for the real mechanics if we get to that after checking simpler things well and rechecking etc..Gracias amigo

[donradcliffe]

Try this first.

https://www.cruisersforum.com/forums...lb-219031.html

[Toccata]

Possibly of interest in this thread.
I too have had issues with my Yanmar 4JH4 TE Fuel pump. Low rpm, would not rev past 2000.
Engine only 127 hours from new.
Fuel Injection pump removed, the fuel flow regulator was worn. Cause was apparently "bad fuel" The boat had spent many years cruising around Thailand.
During the pump rebuild, the wax cold start device was removed and the hole blanked off, with the following explanation offered by the pump rebuilder: The Cold Start device changes the pump timing until the engine reaches 56 degrees (I think that temp is correct) The purpose of the device is so that the engine can operate at full power the moment it starts, [rather than giving it a few minutes to warm up] One of the problems with the CS device is that as the engine coolant temp rises it can "bounce" and create a rough running engine. The other problem is that inside the pump the CS device is connected to a small plastic lever, this is prone to fracture.
As a side issue, the coolant path through the CS device was completely obstructed with "gunk" despite the correct coolant being used, so the device itself was probably not working as designed.

[capitansurfista]

Originally Posted by donradcliffe

Try this first.

https://www.cruisersforum.com/forums...lb-219031.html

Thanks for your time and advice. I like this idea.

[capitansurfista]

Originally Posted by Toccata

Possibly of interest in this thread.
I too have had issues with my Yanmar 4JH4 TE Fuel pump. Low rpm, would not rev past 2000.
Engine only 127 hours from new.
Fuel Injection pump removed, the fuel flow regulator was worn. Cause was apparently "bad fuel" The boat had spent many years cruising around Thailand.
During the pump rebuild, the wax cold start device was removed and the hole blanked off, with the following explanation offered by the pump rebuilder: The Cold Start device changes the pump timing until the engine reaches 56 degrees (I think that temp is correct) The purpose of the device is so that the engine can operate at full power the moment it starts, [rather than giving it a few minutes to warm up] One of the problems with the CS device is that as the engine coolant temp rises it can "bounce" and create a rough running engine. The other problem is that inside the pump the CS device is connected to a small plastic lever, this is prone to fracture.
As a side issue, the coolant path through the CS device was completely obstructed with "gunk" despite the correct coolant being used, so the device itself was probably not working as designed.

Thank you for your time and advice. We will soon get Yanmar mechanic to check this too. Muchas gracias.

[capitansurfista]

Hi Guys, thank you for your feedback I appreciate evryones help. I will let you know what was the problem. Very simple and almost took Injection Pump our etc...
Well, a v good mechanic help me with it as I know Galapagos mechanics are pretty good common sense guys. I was taught by trhem anyway in many ways and also Captains.
So by chance or by Covid few Chater boats came over to where we are to dock from islands. This guy told me the problem was very simple (nobody could fix it for 3 years and I was supposed needed to do it.
What was the problem is this. SOLENOID OF IDLE RPMS BY INHJECTION PUMP SHAFT WAS NOT PROPERLY LUBRICATED. In short for those who know Yanmars and also I have a diesel engine with same thing on my car so I was suspecting something of the sort there maybe...but I had a different problem once in car...
So, if this probl;em happens to you described in Thread. Go for th solenoid and lubricate it with Silicon Lubricant or better solicon grease. Wallah problem gone completely.
Try that. It work for us. Have a great week and keep cruising and surfing...cheers and thanks to all! Hope we meet in the water.

[Compass790]

What a good price fix! Much better than a new injection pump lol.
Thanks for posting the diagnosis & cure. It's frustrating when you dont hear the result when following a thread.
happy sailing & motoring