Tamd 71a 1988

Hi everybody,

I own a 1988 Princess 45 equipped with twin TAMD 71A. Normally I criuse at low revs (1000 to 1200 rpm, 8 to 9 knots) in short distances (4 to 10 miles).

When for some reason I try to get full throttle, the engines will not go above 2200 when max rev should be 2500 rpm. Additionally, while the port engine goes up fast, the starboard revs up slower ans smokes a bit (white smoke) above 2000 rpms. Other than this, the boat runs great and fuel consumption is really low.

Can someone help me on this?

Thanks a lot.

Joao FN

Re: Tamd 71a

Joao

have you ever been able to reach 2500rpm with both motors before, or is this a new problem?

Are propellers damaged? Are they correct pitch for your boat/engine/speed?

Is the bottom of the hull clean?

What is the condition of fuel and fuel filters?

Re: Tamd 71a

Thank you stringer_bell for your help.

I don't know how far this goes in time as the boat was used mainly by my father until last summer. As far as I know the propellers are the original ones, and two years ago the port prop was damaged at sea and after repair the port engine was revving around 200 rpm below the starboard one. This May I removed both props and had the port one reshaped to match the strarboard and now both engines run at the same rev. I don't know what is the actual pitch/diameter neither what should be the correct one. What I can tell you is that at 2200 rpm the boat runs at 24 knots (22,5 knots in GPS), which I find pretty acceptable for this kind of boat. The filters and pre-filters were changed in May and the hull was also cleaned and painted.

Re: Tamd 71a

The starboard engine might be short on power and holding back the port engine in rpm's. They both need to be making full power to reach WOT rpm's. Assuming that the starboard prop is still the original I would first check the boost on the starboard engine to make sure the turbo is spooling up properly and producing enough boost. White smoke at high rpm's is sometimes water from a leaky aftercooler etc. A failing turbo usually will give you black smoke at speed, although leaky injectors can give you white smoke at idle.
I would check boost first (compare engines whilst you are doing it). I wouldn't keep running the engines like this as they are obviously overloading and will either wear out faster than normal or fail completely if you are unlucky.

Re: Tamd 71a

Hi,
I have a kind of similar problem with a single engine craft, I have a TAMD22 wich has been faultless for 10 or more years
However, on the last couple of trips out there has been a slight (only a second or so) hesitance to pick up revs when opening throttle
I`m not known for my careful acceleration so this is something I notice .....
Its not all the time just on a couple of occasions, I suspected it may be turbo related, is there anything I should "look" for maybe on the engine itself when this occurs?
I do notice there is a lever on top of turbo connected to what looks like a suction valve, cant say Ive seen this move at all ?
(apologies to hijack the thread but we sound to have similar problem so may help us both)

one other thing, this is my first post here after registering, is there a way to set the screen width and cause word wrap in the posts, everything is about 4 screens wide

many thanks

norm

Re: Tamd 71a

Hi,

I've been on the boat yesterday and pushed the engines to max for about a hour. The port engine after a while reached 2300 rpm while the starboard stayed at 2200 rpm. One other comment: the white smoke continues after reducing to 1200/1300 rpm.

Thanks for all inputs.

Joao

Re: Tamd 71a

Get your rev counters checked also. It could just be a rev counter issue, although you still need to find where the white smoke is coming from. Is it losing any cooling fluid or running hotter than the starboard engine?

Re: Tamd 71a

Hi,

After using the boat for some hours (I guess 25), I can now confirm that the starborad engine is losing fresh water (not much). Being so, I guess that the heat exchangers might be leaking, letting some fresh water enter the combustion chambers along with the air and causing the white smoke on this engine. Nevertheless I decided to take off all coolers from both engines (2 salt/fresh water coolers, 2 heat exchangers (air coolers), 1 fresh water oil cooler, 1 salt water reverse gear oil cooler, per engine) and have them serviced. The sealing strips and rings look quite old and I will replace them, as well as all gaskets. I hope this solves the problem. Any thoughts or ideas?

Thanks for all inputs.

Joao.

Re: Tamd 71a

OK, here is how it works. Heat exchanger ONLY has SALTWATER and COOLANT in it. NO AIR!!!!! If you are using up coolant, it has to leak out somewhere. Head gasket leak is unlikely, i have never heard of one leaking without previous major overheating problem. Gaskets are made from metal (great), and all water passages are sealed with high temp o-rings. Only water that can enter engine is SALTWATER from aftercooler element. You can easily see if aftercooler is leaking, once removed if the starboard side of the cylinder head passages is spotless clean, its leaking. If it has slight oily residue on the walls leading to the combustion chamber, its not leaking water.

Thank you very much stringer_bell for your help. Now it makes sense. Well, you are scaring me... If what is entering the engine is saltwater, and considering that the engine has been working like this for the past years, I better have it exchanged for a new one! On the other hand where does the coolant leaks to? And where is that leak coming from? All elements from the coolers were serviced and no leaks were found (I have some photos from the elements, should you want to take a look). Could it be from the sealing rings??? They are only supposed to be exchanged every 2000h and my engines have just got to 1000h last summer. Once again thank you for your precious help.

I am not saying your engine is getting saltwater, I was just explaining that it is not burning coolant. You first have to isolate where coolant is being lost. Sometimes it will evaporate quickly on top of a hot motor and its hard to find the leak. Look carefully and follow the coolant path around the motor, its best to do this in the evening with a flashlight, easier to see moisture then in bright sunlight.

However, when seawater leaks into the combustion chamber, you will get white smoke out of the exhaust. Aftercooler has 4 large o-rings ($20 each new), that need to be checked or replaced. Remove aftercooler, AND FIRST LOOK INTO THE AFTERCOOLER HOUSING AND CYLINDER HEAD PASSAGES, make sure they are *NOT* spotless clean.....they should be slightly oily and black (this is normal). If everything on the inside is super clean, its leaking saltwater. Remove ends caps from the aftercooler, press element out from the casing (only comes out one way, obviously press on end with no flange, and use some kind of plate when pushing on the element so that it doesnt get damaged). Then you can replace the o-rings. Sometimes actual element leaks under pressure, and new o-rings can't help that, you will need a known good used element, or a new element.

Yesterday I picked up the coolers from the workshop and I was told that no leak was found. I guess now it can only come from the sealing rings and/or gaskets. Some of the caps (3 out of 8) are a bit corroded and the leak could come from there too. Either way, the aftercoolers were black and slightly oily, which according to you means that no saltwater is entering the chambers. Considering the above, my first conclusion is that the aftercoolers were leaking to the blige. But I still cannot explain the white smoke and the slight power loss at high revs as well as the coolant level drop. The local guys at Volvo are pointing to a wastegate failure, which sounds rather nonsense to me, as I guess it would cause black smoke (not all fuel being burnt) and would not explain the coolant level drop as well. The white smoke means water in the chambers, right? Where the hell is it entering???