TAM61A engines hunting at low idle and smoking

[stevemitchell]

I posted this over at BoatDiesel.com but after several weeks with no responses, I thought I'd try here.

I have two 1988 TAMD61A Volvo Penta engines with about 4000 hours on each in my Ocean Alexander. There were two owners previous to me, and according to the records I can find, they took very good care of the engines throughout their ownership. The original problematic exhaust elbows were replaced/upgraded, and the original air filters were replaced with an airsep system.

In the last year I have spoken to some other owners of TAMD engines, and to a couple of mechanics who have worked on this and other similar engines both in the US and in Europe.

I have several things I'm trying to determine if they are problems and if I can fix them. Here they are in order of priority:

• Rough idle at start
• Sometimes rough idle after being at low RPMs even when warm
• Amount of smoke at start
• Amount of smoke while at low idle even after engines are warm

The rough idle on start is the one that bothers me the most. A mechanic told me it could be from a worn out fuel lift pump. Another told me it's just the way VPs of that vintage start. I can get them to settle down in about 10-15 seconds if I bump the throttles up to around 900 RPM and they sound very nice then. But I think the second problem is related to this one....

Here is a YouTube video I shot of the engines starting up after being cold.


Here is a more recent video after the engines have been running for a minute and stabilized.

I notice quite a bit of what appears to be unburnt fuel on the water. Not sure if that is normal or?

Sometimes even when they're warm, and I have to maneuver around a bit at idle, they start hunting again. I'm thinking this could be something I can adjust with the idle stabilizing screw, but I haven't explored that. I am guessing this could be a good first start.

The amount of smoke at start is a lot, but I have seen some other VPs that are similar. I know using a block heater might help, and I realize this may not be that solvable.

I am curious if it is normal to have a decent amount of smoke when at idle even when the engines are good and hot. It seems like maybe there is unburnt fuel at that point, and the biggest risk/issue is the complaints I have from crew standing near the stern of the boat when docking. I'd love to try to get that fixed too.

General advice I've gotten:

Adjust the idle stabilization screw to stop the hunting at low idle. Seems like the easiest at least for the hunting.

Change the timing from a 61A to 62 to get it to run more smoothly/smoke less. Not really sure about this one - seems like it might cause more problems than its worth, but the person who suggested it has multiple documents and videos showing the success with this method.

Reconnect pre-heaters or add block heaters to cut down on smoke at start. I would really, really not like to reconnect the pre-heaters. I had a scare early on with this boat and the pre-heaters as a result of a faulty key, and their primary purpose is for cold weather starts. Even with them, the smoke was still about the same. Block heaters sound somewhat complicated, and don't sound like they'd eliminate the smoke or reduce it that much.

Other thoughts?

 

[koliver]

TAMD technology is from the 80s. Injection pressure higher than older engines but way lower than newer technology. Smoke at startup is related to all those things that changed as EPA rules tightened up. In other words, you won't be eliminating smoke at startup on those engines.
After warmup, I get no noticeable smoke from my 41s. When I had some serious work done on one a few years ago, the mechanic doing the sea trails tweaked the timing to get rid of excessive smoke at higher rpms. I have no idea what kind of change was involved, but boy, did it make a difference! You might have to ask a VP mechanic what could be done.

My idle is relatively smooth, though it can get shaky enough that I kick it up 50 rpm, then it smoothes right out.

Good luck, and please post your results.

 

[Duvie]

No expert here but...

Check out the videos of my Westerbeke W30. One is of it smoking and another is with a 2 to 3 degree advanced timing and virtually clears up of smoke after 10 seconds or so. The run of the first video had my neighbor show up as he thought there was a fire there was so much smoke.

My 200 HP Perkins lope like yours when cold. Seems to be a pretty common occurrence with older diesels.

 

[Tom.B]

Our 63Ls sound similar during cold start... aaaaaand... I don't worry about it in the slightest. Well, until now I suppose. We don't have smoke, but do get the black soot on the transom if we don't dial in the right rpms for either slow or fast running. Maybe I will ask Dick about the wavering idle the next time we talk.

 

[tiltrider1]

Call Coastal Marine in Ballard. They are the Volvo dealer. Ask for Larry, he can set you up with one of his guys who can do a visual inspection on warm up, letting you know if all is normal or not.

 

[stevemitchell]

TAMD technology is from the 80s. Injection pressure higher than older engines but way lower than newer technology. Smoke at startup is related to all those things that changed as EPA rules tightened up. In other words, you won't be eliminating smoke at startup on those engines.
After warmup, I get no noticeable smoke from my 41s. When I had some serious work done on one a few years ago, the mechanic doing the sea trails tweaked the timing to get rid of excessive smoke at higher rpms. I have no idea what kind of change was involved, but boy, did it make a difference! You might have to ask a VP mechanic what could be done.

My idle is relatively smooth, though it can get shaky enough that I kick it up 50 rpm, then it smoothes right out.

Thanks. This is similar to what I have heard from several other people with TAMD series engines. The smoke at startup won't go away, which I am OK with and understand.

What I am curious about is getting things tuned a bit better so that the smoke goes away once things are warmed up. At higher RPMs, such as slow and fast cruise, there is no smoke at all, which is good.

I've heard similar things about adjusting timing to get things running smoother both at idle and to reduce smoke.

My idle is very nice once things are warmed up, and only gets grumpy once I have been at idle for a long while, say maneuvering into the marina, and then might get a bit jumpy.

Check out the videos of my Westerbeke W30. One is of it smoking and another is with a 2 to 3 degree advanced timing and virtually clears up of smoke after 10 seconds or so. The run of the first video had my neighbor show up as he thought there was a fire there was so much smoke.

My 200 HP Perkins lope like yours when cold. Seems to be a pretty common occurrence with older diesels.

Thanks! That backs up what koliver has mentioned above, and what I've also heard - adjusting timing could help reduce smoke.

Our 63Ls sound similar during cold start... aaaaaand... I don't worry about it in the slightest. Well, until now I suppose. We don't have smoke, but do get the black soot on the transom if we don't dial in the right rpms for either slow or fast running. Maybe I will ask Dick about the wavering idle the next time we talk.

I don't think it is a problem, I've just heard people being able to get it to hunt less, or not at all. For sure, once things are warm it shouldn't hunt, which I have issues with at low idle after being nice and warm and coming back into the marina. It can be a pain because I get really surge-y behavior which means weird bursts from the prop if I am doing close quarter maneuvering.

I also have no smoke at higher RPMs.

Call Coastal Marine in Ballard. They are the Volvo dealer. Ask for Larry, he can set you up with one of his guys who can do a visual inspection on warm up, letting you know if all is normal or not.

I've worked with Coastal Marine many times in the past. Two of my sailboats had VPs and one I had completely re-powered. I've reached out to them several times in the last year.

 

[Ski in NC]

The colder the sea water, the more they will smoke at no load. Aftercooler chills the intake air. Get them started, throw off the lines and GO. Once under load they should burn clean. Nature of the beast.

 

[stevemitchell]

The colder the sea water, the more they will smoke at no load. Aftercooler chills the intake air. Get them started, throw off the lines and GO. Once under load they should burn clean. Nature of the beast.

Yup, thats pretty close to what I've been told about warming them up. No matter how long or how you warm them up at the dock, it never replaces just getting them under load.

I'm hoping to reduce some of the smoke, and in particular, deal with the hunting idle issue even once they're warmed up.