How long til your 3GM starts?

[skunther]

I’m curious, how long does everyone have to crank til their cold Yanmar 3GM30F starts?

I’ve heard everything from instantly to three solid 10 second cranks, plus using compression levers and heat in the air intake, etc.

I’d just like to know what the norm is.

 

[danm1]

3 to 5 seconds on a 3gm30f with 823 hours.

 

[Ralph Johnstone]

Is that with the Yanmar recommended cold start procedure or not ?

For a 2GM20F with cold start procedure, about 3 - 5 seconds.

 

[Foswick]

I can't speak to that engine, but with my Universal M-35B, I preheat for 5 seconds and crank about 3-5 seconds. If it doesn't fire right up, I continue to hold the preheat button a few more seconds, then try again. She always fires up within a second or two - no matter how cold or how long it's sat. Because of this, I wouldn't crank for 10 seconds at a time, on the assumption that, if it doesn't fire up in the first 5 seconds, something else is wrong.

 

[Captain Larry-DH]

If it doesn’t start within about 5 seconds something is wrong. 2 or 3 short cranks should be enough. If not stop and trouble shoot. Repeated or extended cranking can pull water into the cylinders and cause hydro lock, and if that happens it’s game over for your engine.

 

[kloudie1]

3gmf ... a couple of seconds. But it is never really cold here. Even when the outside air temp is pretty cold, the engine compartment is close to water temp, not below around 50F.

 

[degas]

Is that with the Yanmar recommended cold start procedure or not ?

For a 2GM20F with cold start procedure, about 3 - 5 seconds.

The same for my 2GM20. The 2GM20 doesn't even have glow plugs. The manual's cold start procedure is pretty simple, and it works every time.

 

[wpatch]

When temp above 60 and she has been run within 2 weeks 2-3 cranks and once she catches some throttle. If cold and not run for a bit I usually give it too much fuel and it takes about 4 tries. I am impatient. I have been told I should let it crank a little longer and not give it throttle early.

 

[Dalestr]

The Yanmar Multi cylinder GM SERIES engines were entirely without a preheating mechanism. They can be recalcitrant when temps are below 50F depending on condition. I'm not aware of a cold (frigid) start procedure from Yanmar.
Engine rotational speed is critical to get enough compression heat for auto ignition. Heating the engine space or heating intake manifold helps much but generally, you can use the decompression function to get her spinning faster for a few seconds and then engage both fuel and compression. Ideally you'd want the fuel cutoff (shutdown) pulled until just before compression gets engaged. Flooding is not desirable . You may want raw water supply off initially to prevent filling the muffler.
Rigging some fishing line might allow you to pull the decompression levers forward remotely for run mode but use great care to avoid moving engine elements.
BTW The governor always has the throttle at full setting until exceeding say, 200RPM.
This is a good technique also for a weak battery scenario and is routine for hand crank starting.
Other tricks when quite cold is to add a hot mass like a 1" pipe section in the intake manifold or a real time propane torch. Avoid any spray fluids like WD40 as it risks a back fire.

 

[Tally Ho]

I have a 2GM20F, and my cranks and fires on first 5 seconds of cranking usually. I give it 3/4 throttle, and as soon as it starts to catch, I back it down to idle. My engine has a bit more than 2,500 hours on it.

Ambient temps for this time of year are warm…80’s or 90’s F. But even when I launch her in the spring, after not being started for 6 months, she usually fires up in 10 seconds. If not, in the second 10-second crank.

Greg

 

[Jim Legere]

As the old acronym states: RTFM! All will be revealed. Even includes cold weather starting instructions.

 

[Tally Ho]

I have never had to put the compression levers into decompression mode to start my 2GM20F.

i paid attention when I started it today….less than seconds to start after sitting for a few days (but warm ambient temps…85F).

Started in about 2 seconds when I started it to motor in after a sail.


Greg