In looking through the forum, I found your engine starting problem, back in Jan 2005. Our 3GM30F (1990, 4000 hrs) has developed a similar problem of reluctant starting. I’m wondering if you did replace your starter motor and solenoid as mentioned in your post of 12 Jan 05 (the thread was started 7 Jan)? How did the wiring check that Marty suggested come out? I also followed your engine head repair thread, and am wondering if 5 seconds to start the engine is still the case? I’m hoping to get Shaula back to 2 second starts.
Dan, I also had problems starting my 3GM30F and I replaced the wires that go to the starter button to the starter solenoid. Right now there is a harness with a multiple wire connector. I bypassed this and I have never had a problem since. I should also mention that I had to replace the starter button once about a year ago.
Roger, thanks for the suggestion. I suspected a wiring problem also, but I now think I need to get the injectors worked on. When I connect the solenoid directly to the starting battery, the starter motor does great but the engine struggles, the same as when the circuit goes through the key switch and starter button. It sounds like it’s only firing on 1 cylinder for the first 4 or 5 seconds. This only happens when the engine is cold. It’s been over 10 yrs since I had the injectors cleaned and checked, so guess it’s about time. I’m a bit nervous about removing the injectors myself–I had a Yanmar mechanic do the job last time. Any thoughts?
Roger and forum,
Guess I should update this thread, as many of you have this same engine. After ruling out the solenoid and starter motor and its wiring as the reason for the hesitant starting,I decided to make sure that it wasn’t an injector problem.
When we were in NZ in 1997, I had the compression checked and the injectors cleaned and adjusted. Before we left Seattle in 1993, I had bought 3 new injector assemblies, and the NZ Yanmar dealer checked them out also and made sure they were set correctly. So, we’ve been carrying them around for 15 yrs, and it seems like I might as well get some use from them. The original injectors have about 2000 hrs on them since they were checked in 1997. I think I read that Nigel Calder suggests checking them after about 800 hrs. I could figure out which injector(s) is (are) acting up and only replace it (them), but since I already have 3 new ones,. . . .
I was reluctant to install the new injectors myself, but finally worked up the courage and got stuck in to it. The first problem occurred when I couldn’t get the fuel line disconnected from the middle injector. The wrench was rounding off the hex nut, and heat from a small propane torch and anti-corrosion magic spray did no good. So, replacement of the middle fuel line was necessary. To get access to the fuel pump end of the fuel lines, you need to drain the coolant and then remove the 2 hoses that run right in front of the fuel pump. (The coolant needed replacing anyway.) To get access to the middle fuel line at the fuel pump, I had to remove the the forward fuel line.
It was a big relief when the engine started up and seems to run fine now, BUT, the reluctant starting remains! It always starts, but requires advancing the throttle all the way momentarily, and seems to get going one cylinder at a time. I’ve recently been told that other 3GM30F engines in the marina are having similar starting reluctance, and that it is being blamed on changes in US diesel fuel. Are any other of you 3GM30F folks having the same reluctant starting?
Roger and forum,
Guess I should update this thread, as many of you
have this same engine.
the engine started up and
seems to run fine now, BUT, the reluctant starting
remains! It always starts, but requires advancing
the throttle all the way momentarily, and seems to
get going one cylinder at a time. I’ve recently
been told that other 3GM30F engines in the marina
are having similar starting reluctance, and that
it is being blamed on changes in US diesel fuel.
Are any other of you 3GM30F folks having the same
This season Itchen’s 3GM30 has been starting in 5 - 8 seconds when the ambient temperature is above 50 - 60 degrees F. or so. That’s after planing the head and rebuilding the injectors two or three hundred hours ago, which followers of this thread will recall hugely improved starting performance. If it is really cold, say 30 - 40 degrees F., and the first start of the day, it might take a couple of tries, of say 10 - 15 seconds each. As for new diesel fuel, can’t say, we are still running on last season’s last fill-up. My guess is that, since Yanmars don’t have glow plugs, compression is really important. I’ve been tempted to do a compression test, but so long as it starts quickly enough to not overheat the starter, it seems a lot of trouble & expense for little practical gain.
Thanks for the update on Itchen’s 3GM30F starting. Your times for higher temps seem similar to Shaula’s. We haven’t experienced 30-40 degrees starting temps yet. Do you have to give it full throttle momentarily at the start? Does it seem to fire on less than all 3 cyliners at first? I agree that the lack of glow plugs and maybe a bit of compression loss make our engines candinates for slow starting.
On the “new” diesel, my impression is that the change occurred some time ago, maybe a year or more ago. Does anyone know about this? The sulfur content was lowered, and this reduced it’s lubricity, but there’s gossip that the ctane rating of diesel has also decreased a bit. Marty, are you there?
Thanks for the update on Itchen’s 3GM30F starting.
Your times for higher temps seem similar to
Shaula’s. We haven’t experienced 30-40 degrees
starting temps yet. Do you have to give it full
throttle momentarily at the start?
Yes, I advance it 50% or so, or to full momentarily – but only when cold, first start of the day. After that she’ll start instantly in neutral/idle. When it is really cold and has been sitting for a few days in the 30’s - 40’s, I open two or all three of the compression release levers, get her spinning fast and then pop the levers shut one by one. That always works, and is a useful trick that once saved the day on another boat with a frigid engine and almost dead battery (wouldn’t even turn over with the levers closed).
Does it seem
to fire on less than all 3 cyliners at first?
Yes, rattle, stumble, shudder for 5 or 10 seconds than settles down pretty quickly.