Yanmar Issues Still

[charliehows]

thats what those big blankety things are for - damn, i was going to cut mine up for hankies

[s/v Jedi]

Originally Posted by sailorchic34

I have rebuilt injectors on my list for santa. Though he's horribly unreliable now a days. .

Call me hard headed, lord knows it will not be the first time, but with oil usage and high blowby with oily smoke, its pretty much a given that there's a bit O'wenching in my future. Though I'm betting its glazed walls. A compression test will just tell me, what I already know.

I'm actually not too worried about the engine. To me its reliable enough, and I've got those sail thingies, if it get persnickity on me. Really it runs like a top. Now that its starting reliably again, I'm a happy camper. Maybe its a blonde thing. I also use to drive around without a spare.

Yes it starts rather normal again. I would add an electric boost/bleed pump between tank and primary filter. Run it with engine off to check for leaks in what is normally a vacuum side. You can also put a piece of hose on it's output, submerge that in a jar with a bit of diesel and while running check for air bubbles.

If you ever have trouble incl. Plugged filter, running this pump will keep you going for a bit longer. Cheap at the NAPA or similar.

[Tropic Cat]

I can see you've put a lot of research and effort in solving your problem. I'd humbly submit that if a diesel can start in 2 seconds and run fine, your pistons, rings and valves are just fine. It's a diesel. The successful start is a compression test.

I have 2 yanmars in my boat. I've had them both out of the boat for service and I rebuilt one of them myself. They're simple beasts and it wasn't that difficult.

Two things you've mentioned are interesting. One is this is obviously an intermittent issue. I'm in agreement with Carl that this seems to indicate a fuel delivery problem. Just saying that either an air leak as has been suggested or a fuel blockage would cause this. Possibly in the fuel tank itself. I know that I had this problem at one point and had my tanks cleaned, which fixed it. There was crud on the bottom that would get sucked into the fuel pickup. This would stop the engine and cause exactly what you describe on restart. If waves bounced the boat around enough, the crud wandered away and the engine would start normally. Drove me crazy until a 30 year mechanic laughed at me and then proceeded to fix it.

Easy inexpensive things to check.

The other thing is your boat is 25' long and you are way overpowered. There's no way you could possibly run that engine at 2800 RPM which is where Yanmar wants it. Glazed cylinders would be a logical result of running it at low speeds, as there won't be enough load for that engine to work properly. Yanmar Diesels have to work hard, and are designed to work that way.

Bottom line is you need a 2YM or 2GM or keep the engine but put it in a bigger boat. Seriously, if it started today and ran well, you don't need engine work. My suggestion is to find the fuel delivery problem and fix it. Oh, and all Yanmars have blowby. It's not intuitive yet it's normal.

[sailorchic34]

Originally Posted by s/v Jedi

Yes it starts rather normal again. I would add an electric boost/bleed pump between tank and primary filter. Run it with engine off to check for leaks in what is normally a vacuum side. You can also put a piece of hose on it's output, submerge that in a jar with a bit of diesel and while running check for air bubbles.

If you ever have trouble incl. Plugged filter, running this pump will keep you going for a bit longer. Cheap at the NAPA or similar.

An electric lift pump will be in my future. Sounds like a great thing to have.

[sailorchic34]

Originally Posted by Tropic Cat

Two things you've mentioned are interesting. One is this is obviously an intermittent issue. I'm in agreement with Carl that this seems to indicate a fuel delivery problem. Just saying that either an air leak as has been suggested or a fuel blockage would cause this.

Easy inexpensive things to check.

The other thing is your boat is 25' long and you are way overpowered.

Oh I found a banjo bolt a bit moist on the lift pump yesterday. Tightened that and bleed the system and today its starting reliably. I also pulled a pint of fuel from the bottom of the tank today and it was fine, no water/ crud. I was going to crawl around the lazzerette today and check the fittings on the fuel supply, but the engine now desides to be reliable again...

The boat is 34' long, but the water line is 25' long. So lots of overhangs and a bit of a slug. But then I'm not in a hurry either.

[sy_gilana]

Sailorchic, you are Mech Eng no? Your troubleshooting seems to be on the mark. The only advice I can give you is to "divide and conquer". Knowns, and Unknowns must be sorted. While you pull the injectors borrow a compression tester (preferably the one with little graph paper in) and record your readings. Use an IR thermometer to check exhaust heating rates on start comparatively (or use your hand) the manifold should heat up evenly, if not, swap injectors and test again, did the problem move with the swap? This is a pressure related thing. Fuel pressure, compression, etc, as the engine speeds up the compression (cylinder and inj pump) gets better as the leak/s is/are %wise less apparent. EGT is a marvelous troubleshooting tool.
Keep us posted.

[Blue Crab]

Originally Posted by charliehows

thats what those big blankety things are for - damn, i was going to cut mine up for hankies

I was thinking .......(Depends).

[sailorchic34]

Originally Posted by sy_gilana

Sailorchic, you are Mech Eng no? Your troubleshooting seems to be on the mark. The only advice I can give you is to "divide and conquer". Knowns, and Unknowns must be sorted. While you pull the injectors borrow a compression tester (preferably the one with little graph paper in) and record your readings. Use an IR thermometer to check exhaust heating rates on start comparatively (or use your hand) the manifold should heat up evenly, if not, swap injectors and test again, did the problem move with the swap? This is a pressure related thing. Fuel pressure, compression, etc, as the engine speeds up the compression (cylinder and inj pump) gets better as the leak/s is/are %wise less apparent. EGT is a marvelous troubleshooting tool.
Keep us posted.

Yes I've dabbled with mechanical engineering for long time. Really need to get one of those IR thermometers. Another thing to add to my santa list.

Yesterday after adjusting the valves and a half dozen things, while the engine was running, I pulled the decompression levers one at the time. They were all the same, that is they all sounded exactly the same. With the same amount of cutout. Which was a big improvement from a week or so ago when one cylinder was not pulling its load. Sort of like checking carb balance with skinners union (SU) carbs with the cutout plunger on the bottom of them.. You can diagnose just by listening too.

I should note that I spent over 40 hours researching the diesels and yanmar 3gm's over the last few weeks. There is a lot of information out there. Alas not all of it useful.

[laika]

I have the same engine, 3GM30F (2004 build with 2000 hours) and see the same oil leaks in the valve cover / breather bonnet bolts from time to time.. It comes and goes, seemingly with little consistency. I had to remove the head last summer replacing the injectors (one stuck hopelessly after a week of PB blasting). While the head was off at the shop, I had a mechanic come by and he noted the cylinder walls to be "like new", and saw nothing elsewhere in the least bit suspicious or indicative of poor compression. Also did a valve adjustment once everything was back together. Still, the crankcase pressure is enough to sometimes cause the oil weepage from the bolts and oil fill cap. Have not done an actual compression test, but the engine starts up quickly every time. Have also checked to make sure the breather is clear. I never fill the oil up past 2/3 on the dipstick, and the engine never idles except at warm up and cool down.

Anyway, glad you've resolved your firing issue! Here's to hoping the above means something to you anecdotally. Perhaps the crankcase pressure is not all that unusual for this engine? Or at least not that worrisome?

Also, you mentioned your oil turns black really fast. Mine does as well, and I've also thought this seems like a likely symptom of blowby. Along with the high crankcase pressure, you could certainly see that argument. My oil turns black after the first start (Shell Rotella).
On the other hand, from what I've come across, this is fairly typical, especially in an older-design diesel without a drain plug. And, to quote Richard Thiel -- 'Keep Your Marine Diesel Running' .... "You cannot determine how clean or dirty your oil is by looking at it, because today's high detergent oils are designed to turn black almost immediately after use. The only way to really determine the condition of your oil is to draw a sample of it and send it out for an analysis."

Anyway, thanks for the thread. Good reading!

[sy_gilana]

Originally Posted by sailorchic34

Sort of like checking carb balance with skinners union (SU) carbs with the cutout plunger on the bottom of them.. You can diagnose just by listening too.

Aww jeez you give me goosebumps! I learned from a Mr Eric Harwood, on the design team of the Land Rover since '50s. Deceased. He used to race tune Rileys, and all the BMC engines. Even had a 16 valve cross flow head in a Mini, with a Rootes blower on the front. He taught me to balance SU carbs on Jaguars using a stethoscope with two hoses, "...bring it to the middle with your eyes closed." BUT we digress.

Rule out what thou thinkest it is not, that thou knoweth it is not!

Hoping it is not glazed bores!

I have worked on many engines. Some have been in a state where nothing is perfect. If there are say, 5 components required in a machine, the Ηη of the whole is the product of the Ηη its parts. Perfect machine is 1x1x1x1x1 = 100% but if all components are a little worn, .8x.9.x85.x.95x.99=.58 !!

Compare your actual readings to spec, and bang the worst offenders first.

...and good luck fair maiden.

[sailorchic34]

Originally Posted by laika

I have the same engine, 3GM30F (2004 build with 2000 hours) and see the same oil leaks in the valve cover / breather bonnet bolts from time to time.. It comes and goes, seemingly with little consistency. I had to remove the head last summer replacing the injectors (one stuck hopelessly after a week of PB blasting). While the head was off at the shop, I had a mechanic come by and he noted the cylinder walls to be "like new", and saw nothing elsewhere in the least bit suspicious or indicative of poor compression. Also did a valve adjustment once everything was back together. Still, the crankcase pressure is enough to sometimes cause the oil weepage from the bolts and oil fill cap. Have not done an actual compression test, but the engine starts up quickly every time. Have also checked to make sure the breather is clear. I never fill the oil up past 2/3 on the dipstick, and the engine never idles except at warm up and cool down.

Anyway, glad you've resolved your firing issue! Here's to hoping the above means something to you anecdotally. Perhaps the crankcase pressure is not all that unusual for this engine? Or at least not that worrisome?

Also, you mentioned your oil turns black really fast. Mine does as well, and I've also thought this seems like a likely symptom of blowby. Along with the high crankcase pressure, you could certainly see that argument. My oil turns black after the first start (Shell Rotella).
On the other hand, from what I've come across, this is fairly typical, especially in an older-design diesel without a drain plug. And, to quote Richard Thiel -- 'Keep Your Marine Diesel Running' .... "You cannot determine how clean or dirty your oil is by looking at it, because today's high detergent oils are designed to turn black almost immediately after use. The only way to really determine the condition of your oil is to draw a sample of it and send it out for an analysis."

Anyway, thanks for the thread. Good reading!

Oh good someone else with weepy oil. That helps. Really my engine runs really well so hoping it just did not like winter too much. Going to run it for a while and see how it goes.

[Cheechako]

I dont know.... That engine is what... 16hp at 3400 rpm? Probably a 12 hp engine that Yanmar has over-rated at excessive rpm so they can call it lightweight. Run at a reasonable 2200 rpm like she does it's probably an 8hp engine..... pretty appropriate for her boat. I dont see the glazed cylinder wall issue.... unless the engine was idled extensively when new. Most my engines have been idled charging batteries more than they have been used any other way. No glazed issues. It's not unusual to see a 90-120 hp enigne in a 30-34 ft trawler... they dont have any more "glazed" issues than anything else. Truckers idle their engines for 8 hours or more at times.

[Tropic Cat]

Originally Posted by Cheechako

I dont know.... That engine is what... 16hp at 3400 rpm? Probably a 12 hp engine that Yanmar has over-rated at excessive rpm so they can call it lightweight. Run at a reasonable 2200 rpm like she does it's probably an 8hp engine..... pretty appropriate for her boat.

Nah, it's marketing rating is 30hp. The continuous is 17hp at 3400 RPM. The Yanmar Service manual for 1GM thru 3GM is downloadable from this page. Which is less than the 24hp continuous listed for this engine in previous Yanmar manuals. Other than that, I agree with you. Also I didn't realize she had a 34' boat until she corrected me. So, I do stand corrected. I feel it's fuel not glazing and and stated as much.

[Cheechako]

Originally Posted by Tropic Cat

Nah, it's marketing rating is 30hp. The continuous is 17hp at 3400 RPM. The Yanmar Service manual for 1GM thru 3GM is downloadable from this page. Which is less than the 24hp continuous listed for this engine in previous Yanmar manuals. Other than that, I agree with you. Also I didn't realize she had a 34' boat until she corrected me. So, I do stand corrected. I feel it's fuel not glazing and and stated as much.

Sorry, confused this thread witht eh one on the 2GM...

[CarlF]

It's working so stop tinkering.

I can't tell you the number of times I have fixed a problem but decided to just "clean up" a few other things. Before I knew it, I'd broken something else, lost a part overboard, or whatever.

The Perfect is the Enemy of The Good

Or another version I like:

Better is the enemy of Good Enough.