Yammer Problems and Black Smoke

[Soulflyer1980]

I am having a Problem with my little Yanmar engine and I hope someone can help me out.

Its the 3JH3E with a SD40 Saildrive on it, the upper oilseal was leaking SD oil into the engine bay plus my cone clutch was slipping too so I thought its time to get working. I lifted the engine out (since it was a bit rusty here and there and wanted a drain plug fitted on the oil pan) and gave it to a workshop for an overall quick check and new paint. They stripped all the parts off the engine minus Injection pump, Injectors and lines and made a very good job in cleaning and other stuff. They guy I can usually trust to do a good job

While they did that, I kept myself busy with the sail drive and leaped (valve seat paste) my cone clutch and changed the upper oil seal. Done this a few times and am a fairly good mechanic and trust my works is 100%.

So now here it comes, got the engine back, fitted it all back together (easy enough) filled oil and water in and fired her up. When I leave the engine in Neutral and rev her to the max she reaches 4300 RPMs and no (or little) black smoke comes out. (normal behaviour). If I do that with the propeller engaged it only revs to nearly 2000 RPMs and loads of black smoke is coming out and I can feel theres no real power behind it. Before the fix, she was revving with prop engaged to 3500 RPMs with little to no smoke.

Sorry for the long text but I felt I should give all the information I got

Does anyone know what could be wrong here?

Have a good day

Ferdinand

[sailormed]

clutch cone no longer slipping?


Envoyé de mon iPad à l'aide de Cruisers Sailing Forum

[Soulflyer1980]

Not slipping anymore, the cone clutch is engaging now with a soft clang and the prop wash is good behind the Cat. If it would be slipping the revs wouldn't drop but go higher since the load of the propeller is gone.

[MARINE ENGINNER]

Originally Posted by Soulflyer1980

I am having a Problem with my little Yanmar engine and I hope someone can help me out.

Its the 3JH3E with a SD40 Saildrive on it, the upper oilseal was leaking SD oil into the engine bay plus my cone clutch was slipping too so I thought its time to get working. I lifted the engine out (since it was a bit rusty here and there and wanted a drain plug fitted on the oil pan) and gave it to a workshop for an overall quick check and new paint. They stripped all the parts off the engine minus Injection pump, Injectors and lines and made a very good job in cleaning and other stuff. They guy I can usually trust to do a good job

While they did that, I kept myself busy with the sail drive and leaped (valve seat paste) my cone clutch and changed the upper oil seal. Done this a few times and am a fairly good mechanic and trust my works is 100%.

So now here it comes, got the engine back, fitted it all back together (easy enough) filled oil and water in and fired her up. When I leave the engine in Neutral and rev her to the max she reaches 4300 RPMs and no (or little) black smoke comes out. (normal behaviour). If I do that with the propeller engaged it only revs to nearly 2000 RPMs and loads of black smoke is coming out and I can feel theres no real power behind it. Before the fix, she was revving with prop engaged to 3500 RPMs with little to no smoke.

Sorry for the long text but I felt I should give all the information I got

Does anyone know what could be wrong here?

Have a good day

Ferdinand

hi ferdinand
First of all this engine is rated to work at maximum crankshaft output 40hp/3800rpm and not at 4300rpm. the injection pump timing is wrong.did your mechanic start the engine while at shore?

M.E

[Soulflyer1980]

Hi Marine Enginner,

no, the mechanic didn't start the engine while on shore (didn't have the cable tree) or changed anything on the Injection pump (at least he says so).

I have two Yanmars on my Cat and always compare one to the other for any faults or strange occurrences. Both engines rev to exactly the same (4300) RPMs without the propeller engaged, the 'faulty' one just need a wee bit longer to reach there. As far as I remember both engines have revved higher the 4000 since I got the Cat. I have driven about 800 engine hours on both since then.

Thanks

Ferdinand

[Wanderlust]

I would look at the simple things first. Have you checked the prop for barnacles and growth? If the boat has been in the water and this work took some time, that could easily be the issue. Or maybe something wrapped around the prop?

The black smoke is a strong indication of the engine working really hard. If everything is fine with the drive train/prop, maybe there is an obstruction in the intake or exhaust.

My guess is you will find the cause with these checks.

Edit: I now see you said the propwash is good, and you have a second engine to compare with. That reduces the likelihood of barnacles but could still be something wrapped around the prop.

[Soulflyer1980]

Originally Posted by Wanderlust

I would look at the simple things first. Have you checked the prop for barnacles and growth? If the boat has been in the water and this work took some time, that could easily be the issue. Or maybe something wrapped around the prop?

The black smoke is a strong indication of the engine working really hard. If everything is fine with the drive train/prop, maybe there is an obstruction in the intake or exhaust.

My guess is you will find the cause with these checks.

Edit: I now see you said the propwash is good, and you have a second engine to compare with. That reduces the likelihood of barnacles but could still be something wrapped around the prop.

Hi Wanderlust,

Thank you for our Input. I have checked the propellers for growth and both are as clean as they get, plus I rotated them by hand to see how easy they turn. Both sides are turning equally easy with no torque needed to turn them. There's nothing wrapped around either.

I have taken off the Intake Manifold too (for another reason) and there's no obstruction in there either. Kinda hesitating with the exhaust manifold since there's the heat exchanger attached to it. I think thou, since its revving ok without load, that there cant be really an obstruction in there plus that wouldn't explain the black smoke. In neutral the engine revs perfectly normal, with no noticeable smoke coming out of the exhaust. As soon as I engage the sail drive and rev her up, its 2000 RPM max plus loads of black smoke...the propeller turns very easy by hand thou.

Very frustrating with the nice days coming up and not being able to go out and sail I can tell you.

Ferdinand

[Wanderlust]

Ok, so prop problems eliminated (and probably saildrive as well ... and it worked fine before). So then it points to the engine itself.

I keep coming back to that black smoke ... none in neutral but lots under load .... indicative of a diesel working hard. But it revved fine before the work, so it seems most likely related to the work done on the engine itself or the reinstallation.

If you eliminate gases in and out, I would be starting to suspect that the workshop may have adjusted the timing. I'm no diesel expert, so for that or other diagnosis I suggest someone with more experience than me would be better to chime in.

[Kenomac]

Is it a turbo diesel? If so, it sounds like the turbo isn't functioning.

[hamburking]

You say it revs fine in neutral, and smokes when in gear. And the smoke (and low revs) indicate the engine is under heavy load.

This seems to indicate that something is wrong in the saildrive (transmission). Maybe something isn't aligned correctly in there, or some foreign matter got in there and is gumming it up somehow.

[HappyMdRSailor]

Or it could be all gummed up from not having been loaded with your slipping clutch all this time...

Get out and do a little "hammer time"... Run her wide open for a good 1/2 hr+ ...

[tdh1849]

Suggestion, get the tel# for, " Complete Yacht Service" a Yanmar dealer in Ft.Lauderdale, ask for Marc, (USMC) tell him Pat N now in Tampa told U to call.
They know all there is to know about Yanmars and should be able to help U over the phone.

[seasick]

Injection timing on the 3jh3e is accomplished by rotating the injector pump CW or CCW a degree or two around its cam shaft. If the pump took a bump when being taken in or out of the boat or if it was strapped wrong, this could account for it being out of time, smoking under load and not achieving max RPM are classic symptoms of this. It will be difficult to tell if a bump happened before it was painted. Examine closely where the injector pump mates to the engine. There are three bolts holding it in place and you may wish the intake manifold was still off if you need to get to the upper most of the three bolts.

[Truemettle]

I had a perfectly running 20gm20 and one day under power, it started to kick out tons of black smoke, same RPM, nothing changed at the helm. I reduced power and hobbled home. I started on the exhaust and found the mixing elbow was solid blocked with nothing more than a pencil hole. I replaced all the exhaust components my silencer was also suspect. This cured the issue.

[Mikado]

In my experience, black smoke is usually a result of an imbalance in the air to fuel ratio - too much fuel to not enough air. This means either too much fuel is being added to the mix or there's not enough oxygen being supplied to burn the fuel. The most common causes of black smoke are faulty injectors, a faulty injector pump, a bad air filter (causing not enough oxygen to be supplied), a bad EGR valve (causing the valves to clog) or even a bad turbocharger. I would start to diagnose with the easiest and go down the list.

Good luck,

Jeff