Very slow acceleration on new 2ym15 yanmar

[maury]

In neutral it takes about 6-8 seconds after moving lever to high to get engine turning at a decent speed. It increases very gradually.

Engine was installed years ago but never used, zero hours.

1. Before isolating issue to motor I check and adjusted transmission fluid level
2. Air filter was replaced 25 engine hours ago with washed filter type material. Prior filter I noticed at 5-10 hours was disintegrated gone. I had a mechanic prep never used older installed engine for first use and do not know the status of air filter at that time. Tested also with air filter removed, no change.
3. Fuel filter inspected yesterday, both rancor and in engine are clean.
4. I tweaked Spinlock ATCU control unit and, cables tight and adjusted. At first I was confused by this unit using a winch handle as control arm so may have missed other acceleration issues but had a general distrust of the motor and accurate control for docking.

What else can it be, what should I check next?

[barnab]

Is this with propeller engaged or not? If not, what happens if you try to rev up without engaging the prop? With prop engaged, do you actually get thrust or not? Did you check then prop for fouling? Can you turn the shaft by hand? Do you get the same behaviour if you move the gas lever (sorry, no idea what the proper English term is fort hat) directly on the engine?

[maury]

Very slow acceleration on new 2ym15 yanmar
In neutral it takes about 6-8 seconds after moving lever to high to get engine turning from about 900 rpm to 3500 rpm. It increases very Slowly
(CF site note) seems like my initial post disappeared when make a clarity edit. I might repost and request delete of this thread)

Engine was installed years ago but never used, zero hours, now 30 hours after 6 months of use.

1. Before isolating issue to motor I check and adjusted transmission fluid level
2. Air filter was replaced 25 engine hours ago with washed filter type material. Prior filter I noticed at 5-10 hours was disintegrated gone. I had a mechanic prep never used older installed engine for first use and do not know the status of air filter at that time. Tested also with air filter removed, no change.
3. Fuel filter inspected yesterday, both rancor and in engine are clean.
4. I tweaked Spinlock ATCU control unit and, cables tight and adjusted. At first I was confused by this unit using a winch handle as control arm so may have missed other acceleration issues but had a general distrust of the motor and accurate control for docking.

What else can it be, what should I check next?

[maury]

Originally Posted by barnab

Is this with propeller engaged or not? If not, what happens if you try to rev up without engaging the prop? With prop engaged, do you actually get thrust or not? Did you check then prop for fouling? Can you turn the shaft by hand? Do you get the same behaviour if you move the gas lever (sorry, no idea what the proper English term is fort hat) directly on the engine?

With prop NOT engaged.

Prior test with prop ENGAGED it would also be extremely slow acceleration rate. Shaft spins ok and eventually gets up to speed.I did not check prop yet but that is not primary issue since disengaged displays the issue but it will be looked at. Recently painted bottom is only showing minor green from the surface so painted prop I’m expecting might be the same.

[skipperpete]

G’day Maury , 6-8 seconds is a very long delay, are you seeing any black smoke or soot out of the exhaust? There’s a chance that the alternator is holding the rpm from increasing, especially if you have a high output alternator and a smart regulator. On the injector pump there are 2 adjusting screws, both should have a tamper proof wire and seal, make sure these crimped seals and wire are intact. Inhaling the air intake silencer is a bad thing and theres a possibility that the new one is blocking off the intake. To verify or dismiss this theory take out the new intake silencer and run the engine up to max.
To do a test with the alternator load, take off the belt and do a quick run up to max Rpm but no more than 10 seconds, if she spins up easily, the alternator, Reg or wiring is suspect.

[Mickeyrouse]

Have you checked fuel pump and flow to injectors? If your problem occurs in neutral, it will boil down to fuel starvation, constricted air, or overloaded accessories (alternator, water pump">raw water pump, belt-driven fridge compressor, etc)

[maury]

Alternator, brilliant idea. I think I already had the problem but a few days ago I installed a40 amp dc:dc converter so maybe it amplified the issue.

I need to admit I am intimidated doing engine work and am working carefully with research and the mechanics manual through it. With the cover off I notice the water pump belt is loose so there is a positive already here.

[skipperpete]

Originally Posted by maury

Alternator, brilliant idea. I think I already had the problem but a few days ago I installed a40 amp dc:dc converter so maybe it amplified the issue.

I need to admit I am intimidated doing engine work and am working carefully with research and the mechanics manual through it. With the cover off I notice the water pump belt is loose so there is a positive already here.

Smoke Maury, is there exhaust smoke? An overload from any external source could be causing the slow spool up, ….alternator, starter staying engaged, dragging plates in the reversing gear, seized circulating pump , seized or partially seized raw water pump…. Overloads are accompanied by smoke, usually black. No smoke? Start considering the fuel system and governor settings. Has any work at all been done on the engine other than the intake silencer and filters?

[DougR]

Is it running on one cylinder only? Run the engine up to 2000 rpm in neutral and loosen the injector fuel pipe nut, one cylinder, then tighten, and then the other cylinder, and tighten. ( cover the nut & wrench with a rag to prevent fuel spray) Does the engine loose rpm equally with each cylinder? Does one response seem different than the other? They should be about equal.... Perhaps one cylinder is very weak. ( could be a piece of old air filter holding a valve off it’s seat)

[skipperpete]

I just re read a few of your old posts about the struggle with the exhaust system and I’m curios about how that all worked out eventually, an exhaust system partially full of water might cause slow power up…. But 6-8 seconds is a helluva long timeto blow a bit of water out of an aqualock.
I also noticed that you were enquiring about the injector pump governor screws at around the same time????

[barnab]

If you don't feel comfortable don't loosed the fuel injector pipes, leave that to the mechanic. Also ask him about the raw water pump belt, if I remember correctly this needs to be loose, otherwise you ruin the pumps bearings. As long as you get water out the exhaust and no overheating, leave it as is other wise you might create only more problems.


I would remove the alternator belt and check if water pump and alternator can be turned easily. If so, reinstall the belt and remove as much load from the alternator as possible, especially remove the dc:dc converter.



After that, I would do as skipperpete suggested:
Inhaling the air intake silencer is a bad thing and theres a possibility that the new one is blocking off the intake. To verify or dismiss this theory take out the new intake silencer and run the engine up to max.
To do a test with the alternator load, take off the belt and do a quick run up to max Rpm but no more than 10 seconds, if she spins up easily, the alternator, Reg or wiring is suspect.


And let us know if there is any smoke.



Can you post some fotos of the engine?

[maury]

Originally Posted by skipperpete

Smoke Maury, is there exhaust smoke? An overload from any external source could be causing the slow spool up, ….alternator, starter staying engaged, dragging plates in the reversing gear, seized circulating pump , seized or partially seized raw water pump…. Overloads are accompanied by smoke, usually black. No smoke? Start considering the fuel system and governor settings. Has any work at all been done on the engine other than the intake silencer and filters?

Going backwards( now about 30 hours):
5. Troubleshooting acceleration issue.
d. To address #4 I tried to remove alternator belt for a test but it was screwed in-from the back and very tight. I was not able to so instead removed converter wire to remove the recent new load. I’m sure with another hour I could probably get it off. With cover removed I discovered water pump belt is too loose so will be adjusting that next. Has been pumping water abundently.

c. Visually inspected engine fuel filters, did a flow test on closed Rancor filter and bled system. Note mechanic prelaunch wired old pump going from tank to Rancor filter, pump did not work and I was not able to source a new pump locally so he had me buy a simple hand bulb which he installed instead.

b. Inspecting transmission fluid level I have had some confusion. I have read differing directions recently, removed what I thought may have been an excess and then read something else which left me puzzled. Based on capacity specs I think I did the right thing but not sure.

My transmission dip stick has one line about ¼ inch from the bottom, no second line. Initial mechanic fill (see #4) was about an inch above the line on 3” stick. Now after having removed about 6-8 oz. I find myself baffled. It is now just a bit below the mentioned line. Is this correct?

a. Removed air system housing to test. Filter does seem to dampen the motor a bit but does not affect acceleration issue. Could the filter be too dense?

4. Added @28 hours Renogy DCC converter 40 amp last week. 30 hour troubleshooting I disconnected on off control wire last night, today need to double check no amperage passing through unit. No acceleration change after 4-5 min engine warm up. Converter will remain disconnected until acceleration issue resolved.

3. @ 15 hours maybe: On the exhaust elbow I added a 5” riser and vitus vented loop with pee drain about two feet above water line for water coming from heat exchanger exhaust to elbow above the water line. Prior to this from Exhaust elbow to Vitus hose had a loop going above elbow. Now hose is very slightly down stream to vetus. Also improved downward flow at end of exhaust hose.

2. @ 8 hours Adjusted speed control unit cables. Didn’t feel I was getting rpm from motor.. It helped. Also my unfamiliarity with the winch handle control unit had me very confused until I finally figured out the subtleties. After figuring out the subtleties ( maybe at 20-25 hours) is when I think I started noticing the acceleration issue. My whole distrust of the system was overwhelming when I add various docking scenarios to the equation.

1b. @5 hours Noticed air filter contents except metal frame was gone. I don’t know if mechanic had checked it prelaunch. Friend said he uses washed and dried filters from commercial shrimp tank in his vehicles, gave me one and that is present filter. (Is it too dense?)

1. @ 0 hours pre launch had an old timer Marine diesel mechanic review and do engine prep on NEW motor which had been installed sometime since 2005 post Hurricane Katrina by airplane/ motorcycle mechanic who was renovating the boat.

I wish I could clearly say at what point the acceleration issue became an issue. I was dealing with numerous new (for me) boat issues but feel it was much more responsive initially. (Just realized the dyslexic humor of doing this list in reverse, I am a recovering dyslexic).

[maury]

Images

[maury]

Images

[maury]

Last week I did work on water tank and discovered breather hose was plugged. Could this be the case with fuel breather hose and it causing acceleration problem?