Yanmar 3GM30Fe low power when cold

[phantomracer]

This season, I noticed after starting my 3GM30f (e) engine, circa 2001 that it has low power for about 10-15 minutes. I can't get it over 2000 rpm in gear, If I push it, starts to eject dark smoke (unburned fuel I assume), feels/sounds like it is laboring.

Out of gear, it will rev to 3000-3500 easily, with no apparent laboring.

Afterwards, the engine performs quite well, no laboring, decent power. Where it improves, I don't think there is anything caught in the prop.

Engine has a 100a balmar alternator/614 regulator, so that is, naturally, putting some load on it...but nothing like it has been this season.

Engine has an electric lift pump in line as well.

oil looks good, antifreeze looks good, no level drop (or increase!) in either. Air filter is new/clean

No water in the fuel filters, no debris in the fuel filters (Check/changed each year) and look new, buy diesel at a high volume station, pre-filter it with a Mr Funnel at the station. Never had even a drop of water in the water separator. Inside of tank looks pristine.

My gut, is, at 1100 hours, I know I am considerably overdue of servicing/replacing the fuel injectors, so I plan on doing that this off season anyway.

Could it be as simple as that, just a bad spray pattern due to age/carbon?

Is there anything else I should be suspect of, or change pro-actively, that could cause this intermittent performance problem?

Is there any other parts that I need to replace when changing the injectors?

[skipperpete]

Don’t go directly into injector servicing. The fact that the problem resolves after 10-15 minutes suggests a combination of a lightly fouled propeller and a low or Zero B setting in the Balmar regulator, go into the Balmar settings and check the existing belt load values.
Normally neither of these two parasitic loads alone would cause the symptoms you’re describing but combined (and with one of the loads diminishing via the 614 reg) you could see precisely this scenario. Under no circumstances be tempted to adjust the injection limiter ( front governor screw on the timing cover), it’s a difficult process to recover the setting if the factory adjustment is lost (and it’s surprising how many techs try to adjust the limiter without measuring the initial setting)

[SailingHarmonie]

I don't remember the service interval for this engine, but I'll bet it is time to adjust the valve clearances too...

It is not a fuel delivery issue, the black smoke indicates that you are getting fuel in, it is just not burning it when the engine is cold. Not a completely unusual situation for a diesel, but not normal for an engine with such low hours as yours.

We can assume that the engine is getting its normal amount of air, so the issue might be overload, which magically disappears whent he engine warms up, but that seems unlikely.

It might be poor compression, but at 1100 hours that seems REALLY unlikely (unless your valve clearance is off...) or the engine has been abused.

So we come back to injector performance... and as you say, it's about time to have them tested anyway. Usually the only thing you need to change with the injectors is the copper sealing washer. But you would normally get new ones from the testing shop with the injectors.

[phantomracer]

Originally Posted by skipperpete

Don’t go directly into injector servicing. The fact that the problem resolves after 10-15 minutes suggests a combination of a lightly fouled propeller and a low or Zero B setting in the Balmar regulator, go into the Balmar settings and check the existing belt load values.
Normally neither of these two parasitic loads alone would cause the symptoms you’re describing but combined (and with one of the loads diminishing via the 614 reg) you could see precisely this scenario. Under no circumstances be tempted to adjust the injection limiter ( front governor screw on the timing cover), it’s a difficult process to recover the setting if the factory adjustment is lost (and it’s surprising how many techs try to adjust the limiter without measuring the initial setting)

The service interval is 500 hours. At double that now. My thought was if there was not a good spray pattern, would not get good performance when cold, when warm, the warm engine would help compensate and burn the fuel better than when cold.

I did take a Yanmar class at Mac Boring (best money ever spent!) and, at the time (15 years ago) they said just replace the injectors at 500 hours, as the cost of injectors was the cost of testing them! The injectors were like $80 then! Now, what, $300 or so! Not going to replace anything I don't have to!

Valve adjustments are easy to do, and over due by 500 hours too.

Not touching anything that I don't have to! That is for sure! I did just replace the throttle and the shift cables this past winter. got them identical to where they were before.

Yes the belt manager is 0, and is a noticeable load when cold. But did have it in the back of my mind to change that setting.. Need to get myself motivated to go into that programming fun!

Performance Just seems extra bad, late in the season, growth on the bottom/prop did cross my mind too.

[phantomracer]

Originally Posted by SailingHarmonie

I don't remember the service interval for this engine, but I'll bet it is time to adjust the valve clearances too...

It is not a fuel delivery issue, the black smoke indicates that you are getting fuel in, it is just not burning it when the engine is cold. Not a completely unusual situation for a diesel, but not normal for an engine with such low hours as yours.

We can assume that the engine is getting its normal amount of air, so the issue might be overload, which magically disappears whent he engine warms up, but that seems unlikely.

It might be poor compression, but at 1100 hours that seems REALLY unlikely (unless your valve clearance is off...) or the engine has been abused.

So we come back to injector performance... and as you say, it's about time to have them tested anyway. Usually the only thing you need to change with the injectors is the copper sealing washer. But you would normally get new ones from the testing shop with the injectors.

500 hours for injector testing and valve adjustment .

Only get the black smoke when pushed and the engine appears to bog down (over 1500-2000) when cold. Not surprised either. No smoke at idle, or up to about 1500 rpm when cold.. once warm, no black smoke at all.

Only other performance issue I had a few years ago was a check valve (128296-59940) on the injector body (only on select European models) must have been weak, causing starting/performance issues. Replaced that, never not started on the first turn of the key since!

Catching up with normal maintenance, to me, is an important step. As mentioned, I will back off on the belt setting on the alternator regulator (been bugging me for a while!) and I am sure the bottom/prop fouling is not helping, this late in the season.

Was curious if there was something I was grossly overlooking.

[skipperpete]

$150 aud for a new nozzle but here’s the thing, the nozzles on indirect injection engines have a single spray hole you can practically look through and a pin so the atomisation is fairly rudimentary and all the action occurs in the precom chamber, the fuel vaporises and enters the cylinder ready to burn, just add more heat and oxygen… totally different to direct injection engines where good atomisation and spray pattern is critical. Nothing against servicing injectors, but at 500 hrs you’re better off doing a visual inspection of the pintle and a spray test by pulling the injectors out and hooking them up again to one of the injector pump HP pipes, activate the de compression levers ( this is important or you’ll blow out the precom caps) and spin the engine over to observe the spray… if they all look the same, put em back in and spend the money you saved on the suggested 500hr mixer elbow replacement instead.

[AA3JY]

Last time the pre-combustion chambers have been inspected?

[bgallinger]

Originally Posted by skipperpete

Don’t go directly into injector servicing. The fact that the problem resolves after 10-15 minutes suggests a combination of a lightly fouled propeller and a low or Zero B setting in the Balmar regulator, go into the Balmar settings and check the existing belt load values.
Normally neither of these two parasitic loads alone would cause the symptoms you’re describing but combined (and with one of the loads diminishing via the 614 reg) you could see precisely this scenario. Under no circumstances be tempted to adjust the injection limiter ( front governor screw on the timing cover), it’s a difficult process to recover the setting if the factory adjustment is lost (and it’s surprising how many techs try to adjust the limiter without measuring the initial setting)

I would say you nailed it right!

[phantomracer]

Originally Posted by skipperpete

$150 aud for a new nozzle but here’s the thing, the nozzles on indirect injection engines have a single spray hole you can practically look through and a pin so the atomisation is fairly rudimentary and all the action occurs in the precom chamber, the fuel vaporises and enters the cylinder ready to burn, just add more heat and oxygen… totally different to direct injection engines where good atomisation and spray pattern is critical. Nothing against servicing injectors, but at 500 hrs you’re better off doing a visual inspection of the pintle and a spray test by pulling the injectors out and hooking them up again to one of the injector pump HP pipes, activate the de compression levers ( this is important or you’ll blow out the precom caps) and spin the engine over to observe the spray… if they all look the same, put em back in and spend the money you saved on the suggested 500hr mixer elbow replacement instead.

Did the mixing elbow a couple years ago.

[phantomracer]

Originally Posted by AA3JY

Last time the pre-combustion chambers have been inspected?

Haven't done anything to the engine other than normal oil and filter changes.

How does one inspect the pre-combustion chambers? The injectors have never been out of the motor.

I have seen on some websites that there are other parts that should be serviced when the injectors are removed. I Haven't been in there yet, which are prudent to replace, any tricks to them, if I do?

If I pop them out, I just want to ensure I have the proper parts on hand.

I also see , in addition to the quote below:
128275-11410 Chamber
105311-11420 Chamber
(don't know why there are 2 PN for chambers in the diagram (attached)

Fits 1GM, 1GM10, 2GM, 2GMF, 2GM20F, 3GM30F.
REQUIRES:
1-24341-000260 o-ring
1-128275-11500 injector cover washer
1-128275-11490 injector protector washer
2-124950-11450 injector chamber washer
PER EACH INJECTOR

[skipperpete]

Phantomracer, leave the precombustion chambers alone until the time where you need to take the head off for a top overhaul or a leaking head gasket, the sealing washers are expensive and unless you’re fairly good with engines, chances are the precom will get damaged during the extraction process. I only mentioned the possibility of the top half of the chamber coming out to stress the importance of using the de compressor lever as a safety precaution. It’s ambitious to assume that all 3GM series engines are the same, your engine for instance is one of the less common variations with the injector pump permanent bleed device and the totally different injector pipes. There are at least 2 different types of injector nozzle and 2 different types of con rod bolts as well.

[phantomracer]

Originally Posted by skipperpete

Phantomracer, leave the precombustion chambers alone until the time where you need to take the head off for a top overhaul or a leaking head gasket, the sealing washers are expensive and unless you’re fairly good with engines, chances are the precom will get damaged during the extraction process. I only mentioned the possibility of the top half of the chamber coming out to stress the importance of using the de compressor lever as a safety precaution. It’s ambitious to assume that all 3GM series engines are the same, your engine for instance is one of the less common variations with the injector pump permanent bleed device and the totally different injector pipes. There are at least 2 different types of injector nozzle and 2 different types of con rod bolts as well.

Yea, after looking at some videos of people trying to remove the chambers, it looks like it is not fun or at least the potential is there! with the low hours on it, I think it is a good gamble not to touch it at this moment.

Yes mine is kinda of an odd serial number, some unique parts that make buying parts a pain sometimes! Half the time I go into Neimic ..they are like "you have THAT engine! "

How about this minimal plan:

adjust the belt manager on the regulator to reduce the load put on the engine
remove the injectors to inspect (600 hours overdue as it is)
....MAYBE have them serviced.. will see.
Adjust the valves

Check performance next year

question, to get the injector out, have seen several methods. I can't get a slide hammer on as there is no room above the engine. Is the "loosen the retainer a bit and crank the engine to let the compression pop them out " a good method?

Also, I assume I should replace at least the o-ring upon reassembly.

[skipperpete]

You can do a quick check of the alternator by dropping off the belt and doing a short run up in gear against the dock lines, only briefly because the circulating pump isn’t turning. See what rpm you can achieve with that load removed completely.
No to blowing out the injectors BECAUSE, initially the effective surface area exposed to compression is small but as the injector starts to move, the diameter of that fat injector becomes the piston with 400 psi behind it…. You can do it but be completely aware that A.its dangerous and B. the top half of the precom might decide to leave with the injector…. And there’s potentially enough force multiplication to strip the threads of the hold down nuts so keep well clear. I use a heel bar or a wedge but really don’t find em all that tight.

[AA3JY]

Originally Posted by phantomracer

Haven't done anything to the engine other than normal oil and filter changes.

How does one inspect the pre-combustion chambers? The injectors have never been out of the motor.

I have seen on some websites that there are other parts that should be serviced when the injectors are removed. I Haven't been in there yet, which are prudent to replace, any tricks to them, if I do?

If I pop them out, I just want to ensure I have the proper parts on hand.

I also see , in addition to the quote below:
128275-11410 Chamber
105311-11420 Chamber
(don't know why there are 2 PN for chambers in the diagram (attached)

Easiest way to do an “inspection” is by using a cheap bore scope..without pulling. By-the-way..if one has attended a Mack Boring class..’pulling’ pre-chambers is one of the service items presented during the (boat owner) student initiated class completion action item.

Suggest joining FB’s ‘Yanmar Engine Owners Group’ for access to Yanmar Engine service personnel and access to engine specific service files that maybe most helpful.

[phantomracer]

Originally Posted by AA3JY

Easiest way to do an “inspection” is by using a cheap bore scope..without pulling. By-the-way..if one has attended a Mack Boring class..’pulling’ pre-chambers is one of the service items presented during the (boat owner) student initiated class completion action item.

Suggest joining FB’s ‘Yanmar Engine Owners Group’ for access to Yanmar Engine service personnel and access to engine specific service files that maybe most helpful.

I took the class in 2010. We pulled the injector but didnt pull the precombustion chamber ..