Help - YANMAR 4JH2E engine only idles ?

[cruizn]

I've just managed to start a YANMAR 4JH2E but notice it does not rev.
When I engage the throttle I notice the throttle cable does slide in and out changing length but the engine only idles.

I'm guessing that there's an issue with the connect on the engine where it joins to the lever on the governer yes ?

note: This engine has a cold start push/pull cable mounted near the engine as well and whilst the engine was running I pulled the cold start out to see if it affected the engine idle.. It simply stalled the engine and now I can't re-start it. Engine turns over and actually sounds as though it's running for approx. 1-2 sec. then dies.

Any thoughts on this ??

[pcmm]

Originally Posted by cruizn

I've just managed to start a YANMAR 4JH2E but notice it does not rev.
When I engage the throttle I notice the throttle cable does slide in and out changing length but the engine only idles.

I'm guessing that there's an issue with the connect on the engine where it joins to the lever on the governer yes ?

note: This engine has a cold start push/pull cable mounted near the engine as well and whilst the engine was running I pulled the cold start out to see if it affected the engine idle.. It simply stalled the engine and now I can't re-start it. Engine turns over and actually sounds as though it's running for approx. 1-2 sec. then dies.

Any thoughts on this ??

Its Highly Highly unlikely that that "push/pull" cable is a "cold start" and much more likely that it is the engine STOP cable as that is the way its normally setup if you don't have the stop solenoid on the 4JH2E (I have this same engine on my boat). Push it back in and the engine will start.

Check to see that the throttle cable is actually attached to the engine. Should be on the starboard side of the engine. If it is and the engine is still difficult to start, then you likely have a fuel restriction. Clogged filter(s) or fuel shut=off valve at the tank is closed ( been there, done that one)

[cruizn]

Thanks for the reply PCMM

I'll re-check the obvious - fuel shut off valve is not turned to the off position.
The engine cut off is located on the main intrument panel. I pulled it to shut down the engine several times. There is definatley a cold start plunger cable located on the stbd. side it's mounted directly to the engine itself. I'll check exactly what it's attached to.

A friend's thinking if the fuel isn’t getting through quick enough it may have been getting enough to idle and that’s all. So maybe it is the injectors ? Could be gummed up a bit after sitting for too long ...
I sort of feel there's something simpler stopping the engine from starting. (it does actually start but dies immedately) Just not sure why as it was running very smoothly but only idling. I thought perhaps there's an air vent on the day tank that might not be open causing a vacuum. note: I cracked a few fuel lines to check for air lock but only get fuel passing through the lines so looks to be plenty enough fuel.
Hhhmm ??

[skipperpete]

Make absolutely sure that the cold start (cancel device) has returned to the run position, it bypasses the normal Governor function for very cold conditions and the cable often gets corroded and sticks. I can post a screen shot of the mechanism but there’s really not much you can do with it other than adjusting the max fuel stop which is only a pump room tech job anyway.
Operate the engine speed control manually with the cable disconnected to eliminate the cable as part of the problem and check the fuel suction supply and filters too. It might be as simple as air in the fuel or a suction restriction.

[pcmm]

Originally Posted by skipperpete

Make absolutely sure that the cold start (cancel device) has returned to the run position, it bypasses the normal Governor function for very cold conditions and the cable often gets corroded and sticks. I can post a screen shot of the mechanism but there’s really not much you can do with it other than adjusting the max fuel stop which is only a pump room tech job anyway.
Operate the engine speed control manually with the cable disconnected to eliminate the cable as part of the problem and check the fuel suction supply and filters too. It might be as simple as air in the fuel or a suction restriction.

My undertanding from the service manual is the "cold start" is only on the turbo models of the 4JH2E (definitely not installed on my 4JH2E or my neighbour who has the same engine) . but definitly check that but if you aren't getting throttle advancement and it just idles, odds are you have fuel restriction. If the engine is new to you, just replace the fuel filters and bleed everything and go from there.

[skipperpete]

Your’e absolutely correct Pcmm the turbo version had the intake heater and not all 4JH2E’s had the overfuel device and some of the production never had the cable installed , just the control lever on the block side and viewable only with a mirror or a borescope.
From memory its the same injector pump as the turbo model with the boost compensator but I doubt that a cold start was ever needed on any of the 4JH engines

[cruizn]

This is really great advice & yes it has a turbo.

I'll change the fuel filter & drain the old fuel. Will laso check that the cold start plunger is not still engaged with an inspection mirror. Note: I was really surprised at how the engine started first go consdering it sat dorment for over 3 years. It blows a lot of smoke & water from the exhaust outlet. Hope that's just cleaning itself out. When it was idling I was surprised how smooth it idles.

[skipperpete]

I’m interested to know how your engine troubleshooting works out, I’m still hoping for a fuel supply problem as the culprit.... has the engine been in layup for a long time? If so , there’s a chance that the turbo is locked up, though the engine should still run up above idle but she’d be smoky. Has the engine got a large output alternator fitted to it by any chance?

[Bycrick]

I have what appears to be a similar problem with a 4JH2TE. Revs up fine in neutral. With the shaft disconnected, revs up fine in forward and reverse. With shaft connected, won’t rev up in gear. Fuel system is fine. Injectors serviced. Still won’t rev up. Following this thread carefully, hoping for a revelation.

[GreenWave]

Originally Posted by Bycrick

I have what appears to be a similar problem with a 4JH2TE. Revs up fine in neutral. With the shaft disconnected, revs up fine in forward and reverse. With shaft connected, won’t rev up in gear. Fuel system is fine. Injectors serviced. Still won’t rev up. Following this thread carefully, hoping for a revelation.

Assuming this thing is in the water? What’s does the prop look like?

[Ericson38]

Originally Posted by Bycrick

I have what appears to be a similar problem with a 4JH2TE. Revs up fine in neutral. With the shaft disconnected, revs up fine in forward and reverse. With shaft connected, won’t rev up in gear. Fuel system is fine. Injectors serviced. Still won’t rev up. Following this thread carefully, hoping for a revelation.

How many hours on yours? Just a TE (not HTE) ? I just changed the Turbo on ours (4JH2-HTE---circa 1991), the turbine wheel (exhaust side) was caked up terrible at 3000 hours.

What is your engine idle speed ? Was valve lash checked recently? Thinking low compression, valve held slightly open.

Is yours a late 80s engine?

Is your generator getting fuel from the same fuel tank stand pipe ?

Same primary filter ?

So secondary filter is fairly new since this condition ?

Have you used the emergency cuttoff on the rear right side of engine ?

Does it immediately die in gear ?

Take a mirror and flashlight and ensure the turbo compressor wheel is spinning at mid to high idle. If the turbine wheel is fouled, it can block airflow to the point where there is very little power to develop.

Our wheel still spins at 900 rpm, since I just changed the blasted thing. Every oil change, I'm taking off the mixing T to have a look at the turbine side for carbon buildup. Ours is not an oil burner at all, no smoke of any color.

[Bycrick]

Emergency cutoff? That’s a new term for me. Explain please.

[cruizn]

This engine only idles.. does not rev up, even with accelortor lever forward or back.
Engine has 300 hours.
I'll check the turbo compressor blades.
First up I'll change fuel & all filters.
Then if still only idling I'll have the injectors cleaned.
I'll check the accelerator cable linkage as well ( where it meets the governer.

[skipperpete]

There were two different injector pumps fitted to the 4JH2 series, one is the simple inline pump and the other is the Bosch VE rotary pump... the VE pump has an electric stop solenoid on the pump body and is activated to run while the inline pump stop solenoid is activated to stop, which pump is on your engine, it will help a lot to know because if the stop mechanism is sticking on the inline pump the engine would behave as you describe. The VE solenoid will sometimes stop the engine immediately after the key switch is released and idling is unlikely.
I’m assuming that the fuel system from the tank to the injector pump is all ok and the problem is the injector pump.

[Ericson38]

Originally Posted by Bycrick

Emergency cutoff? That’s a new term for me. Explain please.

On the injector pump side, cable with red pull fitting on end, pull to rear, emergency shut down in case of engine run away. Close to turbo intake screen is where the handle is. I have the inline HP fuel injector pump.