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TAMD31B 8kts top speed

S

Stringer Bell

Guest
"Hello all. I am looking for s

"Hello all. I am looking for some help on 1993 TAMD31B. Its a 2.4L turbo diesel 4cyl. It is paired with DP-D outdrive. Props are A8. No separate trim tabs. Has original Penta gauge panel setup, and gauges don't work for the most part. Oil pressure works, voltage works. Electronic trim gauge looks like its working, but if I keep trim switch DOWN it will go from 3-4 trim to 34 "Beach" setting...so not sure about that one. Tach, and engine temp gauge don't work.

I took the boat out for the first time today. Seller claimed 25kts top speed (empty, ideal conditions I guess). I had full tanks (2), 5 people on board, large 150qt cooler, and some light dive gear (freedivers/sperfisherman, so no scuba tanks). Seas were rough approx 5-7ft.

I got up to 7kts or so, going into waves. On way back with wind into my back, and riding waves, it got up to 9kts or so. This is GPS measured speed (Furuno).

I am unsure at what RPM engine was turning, as tach is dead. There is 1850 hours on the motor. Turbo spins but i could not audibly verify if it ever came on (boosted). New air filter. Good oil. Good coolant. Engine runs good, idles good, no issues. I had it running for 3 hours straight without problems. Gas lever would operate from idle to throttle stopper all the way, without obstruction.

I will try and get the tach to work, and temp gauge (looks like loose connection or terminal corrosion). Where does this engine pick up RPM signal, so I can look into it?

I am in West Palm Beach, and ocean/distances of my dive locations are significant, and I need to try and get this boat to plane and run fast(er).

Boat is 22.5' Rigid Bottom Inflatable with center console. 7 air chambers, and regular fiberglass hull.

Here is how it all looks:

http://i45.photobucket.com/albums/f71/zizabgd/RIB/IMGP1772.jpg"

http://i145.photobucket.com/albums/r224/BubblesDepo/RIB/PB150032.jpg"

Please help me with some suggestions as to where to look and what to consider when trying to figure this out. THANKS IN ADVANCE!!!

SB
53607.jpg
"
 
Clarification(s):

W

Clarification(s):

When going full throttle it only achieved 7-9kts.

2nd half (upper half) of throttle handle forward travel produced NO increase in RPMs. There is a large "dead area" where thottle handle movement makes no difference in RPMs.

Merry Christmas everyone
 
"Fully understandable!
1: The

"Fully understandable!
1: The rpm 'sender' is the generator 'W' output.
You need to get above 2400-2600 to get the turbo to 'kick' in.
With that load You may have to go down to A4-5 props to obtain that rpm, BUT when running empty boat You will most probably far exceed the max rpm- 3800!"
 
"Thanks for the FAST reply Mor

"Thanks for the FAST reply Morten!

Do you mean that if I were to take my boat out now, with existing A8 props, and empty load (full fuel, just me on board, no other weight), I should be able to get up to full speed (~25kts), and higher RPM than what I experienced today?

"1: The rpm 'sender' is the generator 'W' output."

What is generator "W"? If my tach is not working, does that mean that I will be unable to reach higher RPM (since generator W is not working)?

So basically I should prop the boat based on expected load during majority of use? Is there anything I can reference online to try and find out what are the prop options and how would my boat respond to them?

Thanks alot"
 
"'W' out put on the ge

"'W' out put on the generator is an AC output. The rev counter counts the AC frequence given by the generator. If generator does not work, You loose the tach, but it does not affect engine performance.
RIB's may be a bit tricky to prop, and particularly in Your case where You might be a bit under powered relative to boat load capacity.
A8 prop may work on a light boat and should give some 30+ knots, but load the boat and You are stuck. The RIB's needs a lot of torque to get planning, but as soon as they are up they just keep on. The smoke limmiter in the fuel injection pump prevents the pump from giving full amount untill You have reached turbo pressure above 0.8Bar which is close to 2600 rpm.
You have then two options, re prop or re-adjust the smoke limmiter.
Another thing You might check is the exhaust 'brake', an electro magnetic flap that should be closed when idling and opens when giving throtle. Located at stb side of the engine and operated by a micro switch at the injection pump. As soon as the throtle starts moving it should be activated. The flapper inside the exhaust may be stuck or the electric/magneto defective.
What is 'on line' of prop selection charts mainly referrs to normal planning boats, the RIB's acts as mentioned above a bit different."
 
"Thank you Morten!

I think

"Thank you Morten!

I think I will start with checking exhaust brake first. That sounds like a possible problem.

I have also ordered a boost gauge, so that I can see what turbine is doing during all this.

I will measure W wire output signal from the generator and see if its a bad connection or bad generator. When replacing generator, what is the name for it? "Tachometer sender unit" or something? I have heard stock tach is usually not the most accurate one, is there an option of installing aftermarket tach that will show me the exact RPMs?

I also just realized that main 3-blade prop is bent slightly, so that might've caused some of the speed issues as well.

Thanks again for great advice"
 
"If generator is bad and need

"If generator is bad and need to be replaced, be sure to get one with the 'w' terminal at the back. Any tach that operates with signals from generator may do."
 
"Generator is Alternator, righ

"Generator is Alternator, right?

Will 15PSI boost gauge be enough for this engine? 0.8kg/cm2 is like 12psi if I am correct, that is 2600rpm and I am not sure how much higher boost gets up to 3800rpm.

Thanks!!!"
 
"Update:

I had a bent 3-bla

"Update:

I had a bent 3-blade (front) prop. Took a rubber mallet and 2x4 board and banged the aluminum back into almost perfect shape (seriously).

Boost gauge I got (Volvo Penta) from eBay is for bigger engines, goes up to 48 PSI! So I am gonna sell that and get a simple 15PSI VDO gauge.

I was able to fix the temperature gauge (corroded sender prong). I was not able to fix the tachometer. Alternator on the engine looks brand new, and works great. I checked all connectors on the back, and they are all solid. I will have to test more with multimeter and see where the signal is getting lost.

I also found something else broken. Its a low profile "neck" just on top of the intermediate unit front. It is connected to this snake shaped hose (so that it outdrive can be tilted up/down without hose slipping off). Neck is broken (corroded), and hose was slipped off.

"Neck" - hose connection (part # 9):
http://media.stemtostern.com/Diagrams/Volvo/dpd12.jpg"

I *think* (and hope) its exhaust related, and that hose slipping off didn't hurt anything, but can't tell.

Please let me know what this hose/connection does, where hose comes from, and where it leads to.

Thanks in advance. Happy New Year everyone!"
 
"UHUUUUU!
That is the raw wat

"UHUUUUU!
That is the raw water hose connector! With the hoose off, now cooling water to the engine!
Lucky You only went 8 knots and the hoose was in water. If You had gone planning, the water pump would have sucked air only!"
 
"Damn....I'll get that fix

"Damn....I'll get that fixed immediately. Sorry for all the questions, I am new to this (in case you didn't know haha).

If you ever need your alu prop fixed, let me know, I do wonders with rubber mallet :)

Happy New Year Morten!"
 
"Did some more tests. Engine i

"Did some more tests. Engine in neutral, and pull the gas lever out, I can then free-rev to 3800rpm easily, engine screams!!!! Sounds super solid and smooth. Replaced both fuel filters. Checked injection pump vacuum line, no restrictions. Under load it still only goes to 1925rpm (checked with digital tach), and 7-9kts. Friend suggested to pull injectors out and check them, but if its super smooth and strong free-revving, is it possible that injector is bad/clogged? Doesnt make sense. He says free-revving is different when revving under load. Don't know where to look at this point, thanks for any suggestions"
 
"Providing not fuel related, u

"Providing not fuel related, unhook the fuel return line and let it run into a cannister, if it stops running -You have a fuel supply problem.
Further check both air and cranck case ventilation filter. (You may do a short test without them). However at only 1925rpm the turbo will never kick in, You need 2400-2600 at least."
 
"Thanks Morten! Air filter is

"Thanks Morten! Air filter is new. Turbo spins fine. Since I have two gas tanks, there are some levers (two per tank) that open/close fuel supply, I will experiment with them and see if I can get the fuel supply to work properly. I think that might be it....I'll post what I find tomorrow afternoon. Thanks again"
 
Don't forget the cranck ca

Don't forget the cranck case vent filter. Located port side aft on the engine!
Then the diesel filters and the screen filter in the fuel feed pump (under the top lid).
 
"Ok, here is more info.

Air

"Ok, here is more info.

Air filter is new
Diesel filters are new (both factory and aux)
Turbine spins freeely (tested compressor side)
No excess smoke out the exhaust (I think that rules out leaky injectors and bad turbo)
- I was not able to find the crank case filter yet, to replace

When testing the engine out of the water, I can rev it IN NEUTRAL, and it revs to 3800rpm, without any issues. When I rev it IN GEAR (props spinning), same result, props spin like crazy and 3800rpm is reached easy, sounds perfect.

However, when I take it into the water, and try to run it (just me on the boat), it won't rev past 1900rpm and gets up 9-10kts tops. It almost gets on the plane, but the engine simply is running/revving at what looks like half capacity.

Where exactly can I look into "exhaust brake" to verify if the gate is opening under load?

Also, does Volvo sell factory service manual for these older engines?

Thanks

PS I opened both gas tank feed levers to eliminate any fuel supply issues."
 
"The exhaust brake, if not bei

"The exhaust brake, if not being removed, is located at port side. Magneteo a bit low down, then a 40cm rod going backwards up to the exhaust outlet. Inside is a flapper that is operated ny the rod. Check that the rod may move up and down by hand (flapper is not stuck), then when engine running and throtle is advanced the rod should be activated by the magneto. However stop reving Your engine unloaded, it does only dammage and gives no answer. Did You do the test by disconnecting the fuel return line into a cannister to check that You have enough fuel?"
 
"Thanks Morten. I still have t

"Thanks Morten. I still have to check fuel return. I only revved engine unloaded 3 times, to test it. Now I know its not really any indicator of what actually happens under load. I will concentrate on fuel system"
 
"If fuel system tests out ok,

"If fuel system tests out ok, try to borrow a set of A5 props. My experience however tells me that the best option might be to install a set of Bennet (or similar) hydraulic trim tabs."
 
"I went over this today with J

"I went over this today with JD from Marine Parts Express. For my boat lenght and weight, and high drive ratio (2.3:1) - A8 is correct dual props (even tho they rarely sell props that high in pitch, and only to 300-400HP engines). He also suggested A6 or A7, just to eliminate props as problem. I will try to eliminate potential issues one by one and see where that takes me. Fuel is #1 on the list now, I'll post what I find

Thanks again, have a nice weekend"
 
"JD might be theoretically cor

"JD might be theoretically correct conciddering only boat wheight and length. However add the 'RIB factor which means the center of gravity quite far aft, resistance in pontoons when going planning (they have to pumped rock hard), bottom angle etc and the fact that You need min 24-2600 rpm for the turbo to open the fuel pump. Had it been a KAD engine it might have been slightly different, but Your engine - I know them too well -I used to have a pair of them myself in a 5 tonns 28 footer!!!! (My pumps was not at factory setting, but that is another story!)
I know that A5 might bee far to low when planning, but will give You the possibility to get planning! General problems with RIB's is that You need to be planning before You reach 1/2 of available rpm if You want full advantage of the package. You might at best be planning haveing used 60-70% of available rpm and will thereby 'miss' the top end speed as it will be limmited by rpm, unless You do a 'naughty' adjustment of the pump!
But this You will find out!
Enjoy Your weekend."
 
"Hello Stringer Bell,

I&#39

"Hello Stringer Bell,

I've sent you a "dropload" with the workshop manual of the TAMD31B, hoping it can give you more insight on this engine.

Unlike the A version of this engine, the B has no exhaust brake , so the problem is to be found elswere.
If the problem exists only in loaded conditions, the prop is ok, and the bottom of boat is clean, check the pressure of the dieselpump, and injectors, and the timing of the pump.
See attachement for specs.

success, Paul.

53979.jpg
Problemshooter
 
"Thanks for all your help!!!!

"Thanks for all your help!!!! I got the boat to PLANE! Installed B4 props from gas Penta and it went on plane right away, took it up to 3175rpm and was going 17kts into the wind and chop! Rides very smooth. Fixed raw water pickup neck, and temp gauge sensor replaced. I was severely overpropped for the RIB with those A8s. I will take it to 3800rpm on a calm day and see how fast can I get it to make sure B4s are safe. THANK YOU MORTEN (especially) for your time and help, I willdo some more tests and post here."
 
"Congratulations to step one!

"Congratulations to step one! However unless You want some heavy expences on Your drivetrain and steering system I suggest You change to A props, and A5 would still be my first choice.
Do the testing with Your normal load, and concentrate on the planning power. Whatever makes You plan, will probably even hit the top rpm!
On of the 'naughty' tricks to do is to reduce the tension of the smoke limmiter spring at the pump, but don't mess with it Yourself, get someone who knows the pump system to adjust. It will make the pump encrease the injected amount of diesel during acc, but the down side is the black smoke!"
 
"Thanks Morten!!!

Now that

"Thanks Morten!!!

Now that I know engine is fine, I will sell two sets of A8 props that I have, and get some A5s or something. These B4 props (both 3 blade) were in the back of my local (retired) mechanics workshop for few years, he gave them to me for free to try out, and I only used them to eliminate props as a potential problem. B4 are from gasoline engine, and in the chart they show that they will work almost perfectly. How bad is the extra load on the driveline and steering with them, compared to A-series? I don't plan on going over 20-22kts ever, and approx 3500rpm. Cruise at 3200rpm and 17-18kts approx, with loaded boat.

That same mechanic is going to fix my tachometer, so I don't have to use digital tach pointed at crank pulley under the engine cover WHILE riding into chop and wind! I will not play with the pump for now, maybe later hehehe! Will "tuned" pump emit more smoke at idle, and at lower speed as well? I will almost always have divers in the water, and since they are breath-hold diving (freediving) they will not appreciate the addition of excess diesel fumes into their lungs haha Right now fumes are barely noticeable at idle and at low speed."
 
"The risk of dammage running B

"The risk of dammage running B4 on Your engine is difficult to state, I just know from my experience when working at Volvo Penta sweeden back in late 70 -early 80 when we were in the final testing stage of the duo props that propellere selectons was the biggest problems. We broke steering arms, bent and broke inner shafts and You name it. Even broke arms and shoulder of our test drivers due to unexpected steering forces in certain cases! Never run a duo prop without power steering and proper prop setting is my advise! But who knows, perhaps is a B setting perfect for Your RIB? You may get an idea if You disconnect the power steering ( take the belt off the pump) and gives it a try, just be careful!

Playing with the spring tension of the smoke limmiter will not affect smoke in idling or top end performance, only during acc. But as I said, I recommend You to get some more info about how it works before playing with it. Do it wrong, and You may have to send the pump to a Bosch dealer for re-setting and adjustment."
 
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