Yanmar 1GM starting issues

[Hunter27]

Hi All, first post..

I'm still a newbie, have had a 1981 Hunter 27 with a Yanmar 1GM engine for 2 years.

Recently, when I hit the start button it almost sounds like something is 'grating', and the engine has big touble starting.

However, if someone holds up the compression lever, it will catch and start spinning, then start as soon as the lever is dropped.

This started right after a tropical storm (Hanna) blew through about a month ago, but I don't know if thats a coincidence.

Secondly, I have trouble keeping the RPMs up past about 2500 when in forward or reverse, but in neutral I can I can get up to over 3000. Other owners said it was a fuel issue (and I had no clue how old the fuel was) so I recently had the fuel polished, but no real change.

I have kept up on maintenance in my limited newbie fashion; All filters and oil changed every 4-6 weeks.. The primary filter glass bowl is clear and pink, no water.

Do diesels have trouble maintaining power if under stress due to wind / tides?

I'm totally at a loss and hope that someone has experienced something similar before.

TIA

[Chief Engineer]

Sounds like a starter problem first.

Check and clean and secure all battery connections first.

Make sure the starter is tight on the engine.

Post back and keep us advised

There is a lot of help and fun on these boards....

[Hunter27]

Originally Posted by Chief Engineer

Sounds like a starter problem first.
Check and clean and secure all battery connections first.
Make sure the starter is tight on the engine.

Hi Chief (and all), thanks for replies.

I replaced the starter about 5 months ago, because it would just 'click' when I pushed the start button, and take several attempts to actually 'bite' and power up.

However, the new one does that too (I am assuming the click is teeth hitting together, not engaging?)

Have also tightened down the battery, checked connections at both ends, and run a meter to check levels.

My first thought after the storm was that water had been forced up through the intake, but I've run the engine at least 3 hours since then, wouldn't it have gone now?

Thanks again for the replies

[Ex-Calif]

Symptom 1 - Is likely a starter bearing, or bendix (the thing that meshes the gears together) - if it spins up the engine with the compression released I am gonna bet starter motor.

Symptom 2 - Is there any smoke? Does it consume oil? Has the engine ever been overhauled or replaced?

In your 2 years of ownership have you had the bottom scrubbed, including the prop? Where do you sail? Build up of fouling on the hull and prop could be a cause of the power issue. In our area we have to clean the bottom about every 2 months as we have very active growth. Once the prop gets a barnacle build up we are lucky to get 1800 RPM.

[bill good]

I would say that the 1GM is known for this starting issue so take it slowly & don't start spending until you are sure. I learnt the hard way. I have twin 1GMS in my cat and after 15yrs still fixing things up. The voltage drop over old heated wiring/plugs are a concern. Some people have fitted a relay to overcome this. It has the appearance of low batt volts or faulty starter & in some cases it might be the case. Put a press to start button in the lift ring on the motor & wire it direct to the starter cct may be a simple test & you can start the engine this way.

Regards Bill Goodward

[Hunter27]

Originally Posted by bill good

Put a press to start button in the lift ring on the motor & wire it direct to the starter cct may be a simple test & you can start the engine this way.

Hi Bill,

That sounds interesting, but I can't visualize exactly what you mean by the lift ring.

Do you mean basically 'patch' a second start button in the engine compartment, straight to the starter?

[Hunter27]

Originally Posted by Ex-Calif

Symptom 1 - Is likely a starter bearing, or bendix (the thing that meshes the gears together) - if it spins up the engine with the compression released I am gonna bet starter motor.

Hi Ex,

Everything keeps aiming back at this little sucker.. How fast do these 'go bad'?

I guess I could put my old one back on and see if it's still the same.

Originally Posted by Ex-Calif

Symptom 2 - Is there any smoke? Does it consume oil? Has the engine ever been overhauled or replaced?

Yes, there is white smoke when 'under duress' (if I go from say 2000 - 3000 rpms quickly), but that doesn't last long, maybe 20 seconds.

No noticable oil loss, but some oil is usually ejected with exhaust after I have just changed the oil and/or filter.

No clue about overhauled, but still original 1981 engine.

Notes: The power loss can suddenly 'correct itself' for no reason, e.g. it can go from 3000 to 2500 and stay there for several minutes, then suddenly go back up again.

Also, if I reduce the rpms down to say 1500 for 5 mins or so, then push it back up, it will go back to 3000 for a while.

All of that pointed to fuel, which is why I had the system polished.

Originally Posted by Ex-Calif

In your 2 years of ownership have you had the bottom scrubbed, including the prop? Where do you sail? Build up of fouling on the hull and prop could be a cause of the power issue. In our area we have to clean the bottom about every 2 months as we have very active growth. Once the prop gets a barnacle build up we are lucky to get 1800 RPM.

We sail on the southern Chesapeake Bay VA, previously Albemarle Sound, NC.

She was hauled this year, literally 3 months ago. Bottom repainted with Ultima SR, prop & shaft cleaned of barnacles, plus many 'maintenance' items including engine (oil / fuel / filters / impeller / zinc, etc).

I suppose I should go under and check the prop for barneys. How fast do they grow?

Thanks to everyone, hopefully we can get these things figured out, it's really not good knowing if this thing is going to suddenly fail on me when I need it most.

[Tropic Cat]

The gear nashing sounds like a starter problem to me as well. They are very sensitive to voltage drops and this could be a connector / wiring issue. As for the sudden drop in RPM this sounds like air bubbles in the fuel line. There are three main fuel bleeding points.

1. engine mounter fuel filter near the air intake.
2. input to the injector pump right above the pulley on the front of the engine
3. injector fuel line. On the injector which is on the right side of the engine as viewed from the front.

Take 10 minutes to bleed air bubbles out of the system before you start to spend money.

More specific questions can be answered here

http://www.freeboards.net/?mforum=yanmarhelp

These are great little engines. I have two of them in my boat and absolutely love them (when I'm not complaining about poor quality diesel fuel)

[Hunter27]

Originally Posted by rickm505

the sudden drop in RPM this sounds like air bubbles in the fuel line. There are three main fuel bleeding points.
Take 10 minutes to bleed air bubbles out of the system before you start to spend money.
These are great little engines. I have two of them in my boat and absolutely love them (when I'm not complaining about poor quality diesel fuel)

Thanks Rick, I will double check those. I have had them all open to bleed air out at some point during my tenure, I have been wondering if maybe something is letting air in when at high rpms / under stress.

As for reliability, I still love this engine despite these issues, it is a sturdy workhorse, but yes, the fuel is a pain..

[rtbates]

I also have a 1GM in my Cape Dory and while I can't really offer any ideas on your root cause, I do have one thing I can add. The exhaust elbow is this engines biggest one failure item. What happens is that the cooling water over tome corrodes thru the internal pipe totally unknown to the operator becasue there is no symptom or problem, YET. This allows the cooling water to enter the exhaust flow right at the exhaust port. What happens is every time you shut down cooling water sits in the exhaust port. Over time a hole will develop in the exhaust port into the engines push rod galley. I've even heard of water on shutdown entering the combustion chamber via an open exhaust valve enough to cause a hydraulic lock. No matter what you do/find IF you haven't had the exhaust hose off and inspected the exhaust elbow, do it sooner rather than later. Last summer I had to put a new head on my 1GM for this very reason. It's also why Yanmar recomends that the exhaust elbow be carried as a spare.

good luck

[Hunter27]

Originally Posted by rtbates

What happens is every time you shut down cooling water sits in the exhaust port. Over time a hole will develop in the exhaust port into the engines push rod galley.

eek..

Thanks, I haven't looked into that.

I am assuming where the exhaust hose connects at the middle top left (from front)? Is this something I can tell by pulling the hose off and looking/feeling in, or is it something I need to disassemble the elbow?

[rtbates]

Originally Posted by Hunter27

eek..

Thanks, I haven't looked into that.

I am assuming where the exhaust hose connects at the middle top left (from front)? Is this something I can tell by pulling the hose off and looking/feeling in, or is it something I need to disassemble the elbow?

You'll have to pull the hose off (best to just slit it at the ends for removal and replace) and then take off the THREE nuts holding th eelbow to the head and pull the elbow off the head so you look into the ends and see if there is any corrosion. Use something like a screwdriver to puch on the sides of the inner tube walls to detect a wall about to collapse. As an incentive let me say that the cheapest head I found was $500, but at least it contained all the valves and springs! Also pay real close attention the external oil lines, especially the one that runs just below the water pump. IF they go you're for a big mess at best and a new engine at worst. They are cheap(compared to an engine rebuild or replacement) and easy to replace. If you don't already have one I highly recommend getting a shop manual. It details every aspect of this wonderful little engine.

Good luck

[starfish62]

Might the "click" be a bad Solenoid? If the starter was swapped out & the sound recurs, that'd be a suspect.

[Hunter27]

Originally Posted by starfish62

Might the "click" be a bad Solenoid? If the starter was swapped out & the sound recurs, that'd be a suspect.

The click has recurred across both the starter originally in place, and the replacement I put in a few months ago.

Isn't the solenoid inside the starter motor unit? If so what are the chances both would be bad?

The closest thing I can think of is it sounds like metal hitting metal, which is why I thought it was the teeth on the starter hitting the teeth on the huge wheel in the engine, and it just took a few tries to get them to interlock.

[GordMay]

Originally Posted by starfish62

Might the "click" be a bad Solenoid? If the starter was swapped out & the sound recurs, that'd be a suspect.

A single click, generally indicates low voltage, or a bad solenoid, or both.