Transmission, Turbo, Tachometer, oh my...

[ctlionsden]

I'm just wondering what the prop size/pitch is on your boat. Is it possible you are considerably over-propped (too big, or too much pitch)?
– Lionel

[jleonard]

Just got back from sea trial. WOT only 2100 rpms 17 to 18 knts. No black smoke. No sign engine is stressed or overworked. Could hear new turbo (forgot how good that sounds). I've concluded that I must have some sort of fuel restriction or throttle problems.

When you are at WOT you need to check at the injection pump that the fuel lever is making complete travel and going to the stop.
And did you check no load WOT rpm? Again the lever must travel to the stop. You should disconnect the cable and check right at the engine moving the lever full travel with your hand. Same under load. You'll need a "throttle man" to help you.

You really need a hand held tach and get your boat tach calibrated or all this "troubleshooting" is bogus.

[jruesr]

I think Jleonard could add a lot to this if he would expand information relating to the boost pressure and exhaust gas gages and the readings to be expected on our 6bt engines. According to records at by prop company, my boats previous owner had my engine prop at a higher pitch than I do. He needed a higher pitch in order to slow the engine down to spec. I wonder if I am getting the power that I should. I have a hand held temperature laser (also cheap at harbor freight) and could check exhaust manifold etc if I knew what I was looking for. Also a temporary air pressure gage could be rigged for test easily.

John
Passages III

PS: When you do calibrate your tach be sure and make a note recording how much you changed the reading. You have a lot of old data and you will be glad if you can reference it by correction factor in the future.

[jleonard]

It depends on the engine, but an aftercooled 6BT should be up around 30 psi of boost pressure, EGT should be not much over 800 F. You have to consult the spec sheets.
I had 6BTA 270 hp in my previous boat. It would bury the 30 psi boost gage and EGT was just shy of 850 at WOT as an example. I was 30 rpm over rated at WOT at 2630.
Boost depends on engine loading. If the engine is not loaded you won't make boost. If you don't have fuel you won't make boost.
If you have black smoke your EGT will run high. If you are getting lots of boost and hot hitting rated rpm your EGT will run high.
Specific info will help troubleshoot YOUR particular boat once you establish some baselines. Above is only a few examples of how it might help.

[Seaslug44]

Prop size was never changed. She is perfect size/pitch. When boat was newer she actually cruised at 20 knots and wot was 24 knots so I know its the right pitch/size. With the new turbo, new transmission, new injectors and a half dozen other new parts I'm expecting her to be right back in that performance range. The fact that I'm obtaining 18 knots at 2100 rpms with full fuel tanks & full water tank suggests that she will. I just need to solve this fuel supply problem.

Please see the attached troubleshooting guide that Tony Athens from Seaboard Marine was kind enough to send to me over on Boatdieslel.com. Each of you have given me valuable advice that Tony also mentions. I have my boat yard proactively trying to solve this problem too. I agree that we have to first photo tach the rpms to see how close the tachometer is to reading what the engine is doing. Then we will follow everyone's advice by checking the throttle, the pressure & vacuum readings. One thing Tony suggests but I was wondering if someone could explain to me how it effects performance is the check valve on the return line?

[jleonard]

See # 7 on Tony's troubleshooting guide. If it is not allowing full flow this could be hurting you.
That said, I never had a check valve on any of my return lines that I knew about.

[RobS]

Prop size was never changed. She is perfect size/pitch. When boat was newer she actually cruised at 20 knots and wot was 24 knots so I know its the right pitch/size. ..

Be sure when making this comparison to "then" and "now" you take into account any additional weight added to the boat, small things over time certainly add up, and the condition of the bottom paint too...

[Seaslug44]

Prop size was never changed. She is perfect size/pitch. When boat was newer she actually cruised at 20 knots and wot was 24 knots so I know its the right pitch/size. ..

Be sure when making this comparison to "then" and "now" you take into account any additional weight added to the boat, small things over time certainly add up, and the condition of the bottom paint too...

Yes I thought about that too. Thank you. That's why I am on a mission to go through every storage compartment and remove everything that we loaded on the boat that is seldom used but never took off. I easily spotted 200 lbs or so of "stuff" that I can leave in a locked dock box instead of lugging around with us out at sea. Cleaners, tow tubes, gallons and gallons of extra motor oil, a second backup anchor & chain, old batteries, every size fishing rod imaginable... the list goes on and on...

[jleonard]

I easily spotted 200 lbs or so of "stuff" that I can leave in a locked dock box instead of lugging around with us out at sea. Cleaners, tow tubes, gallons and gallons of extra motor oil, a second backup anchor & chain, old batteries, every size fishing rod imaginable... the list goes on and on...

$hit, I hope the frst mates don't read this post. You are giving away MY secrets too ....and we always blame them for lowering our boat's profile....

[jruesr]

I find it very interesting that you always come back to the same RPM and the same speed exactly. New turbo vs old one, new injectors vs old one etc. Why always 2100 rpm.

Fuel restriction, in my experience, gradually worsens and would not seem to be that repeatable.

We have the same boats (model and year).

Just one quick check you could make to verify fuel tank pick up restriction would be to open both tank valves on the intake and return. My boat is plumbed with a "T" in each line (supply and return). This is how Albin supplied it I believe. I know most boats have one valve that you operate to select one tank or the other but on my boat you can draw fuel from both tanks simultaneously. I could draw from one and return to the other or draw from both and return to both. This is not a great setup because I could forget and draw from one and return to the other and overfill the tank used for return.

If you are piped and valved this way, then you could (for a short trial) draw from both tanks and return to both tanks and see it the speed/performance is affected. Also you could try one tank and then the other tank and see if there is a difference. My fuel pick up tubes were badly clogged and perhaps yours are also. Its an old boat with old tanks so they should be suspected.

One more question for you. Are you sure that we have the same transmissions. I have attached a sketch from the manual. What happened to your transmission that caused you to remove it and repair it. Did you have to take the engine out to get the transmission out of the boat. Its too bad that you have not checked the ratio of the rebuilt unit with a hand held tack by checking its input and output speeds like I suggested early on this discussion. Maybe it is your gear ratio. This check would take me about ten minutes and could be done while sitting in your slip tied off with some good dock lines.

Also my yard thinks my transmission is possibly the cause of my boat shaking. I am very interested to know what happened to yours and why and how you repaired it. Did your yard look for a replacement transmission (different brand/model etc) that would be serviceable with parts available etc. What was the outcome.

I plan to take my boat out of the water next week. I will be strengthening the rudder area and making panels to cover those windows in my kiel area/shaft access.

John
Passages III

[Seaslug44]

Yes we have the exact same boat in almost every aspect. I have the same plumbing on my fuel supply (four valves to keep track of). I am going to have some very specific answers starting this weekend. I did take your advice and ordered a photo tach. That will be my first action- to measure the rpms and compare it to what the tach is saying in nuetral and then in gear. I will then take measurements at the output shafts on both the transmission and the v-drive so that I can be 100% confident that I have the correct ratios.

Next I plan to troubleshoot my fuel supply. I purchased a vacuum gauge for the top of my Racor filter that I will install and take readings before I make any changes. It is supposed to show zero pressure with a new filter element installed. I'm actually kind of hoping that it shows fuel vacuum pressure that is off the charts when I am at WOT. That would then confirm that I have a fuel restriction problem somewhere from the Raycor back to the tanks. Either way I plan to completely unassemble the Racor, clean the interior and reassemble with a new filter. Then I have to clear the vents on each tank. I know they are both clogged. Not sure if its the actual through-hull fittings or the hoses. In a way I may have been very fortunate that both vents were clogged while the boat was layed-up last year because sealing the tanks off from the open fresh air would have actually helped reduce condensation and algae growth (although I have kept the fuel in both tanks well-treated the entire time).

Next I plan to locate those tank access panels, open them up and take a peak at what my pickup lines look like. hopefully I will be able to simply clear any obstructions and blow air through the hoses to make sure they too are clear. By the way, when I open those access panels, will I be able to see my sending units for my fuel level gauge? I have either a fauly sender or a short that causes one of the tanks to violently bounce the needle back and forth between two readings without the boat moving or rocking. I installed a new fuel gauge and the problem is still there so I know it's not at the dash. Anyone know what would cause this?

After that I plan to send a siphon down to the bottom of each tank to take samples and see if I have sludge and/or water at the bottom of the tanks. I will determine what action to take with that depending upon the findings. Next I will once again replace the on-engine secondary fuel filter (just in case the one I installed earlier this year is somehow defective or clogged). I will also confirm that my throttle linkage is correctly opening up the throttle to wide-open on the engine.

Hopefully at this point my problem will be resolved. If not then I may have to start removing and replacing fuel supply lines. Does anyone know what is the correct size and type and whether or not West Marine sells the stuff in rolls or by the foot in their retail stores?

John, in regards to the transmission I doubt very much that your vibrations are being caused by the trani. I am very confident that it's the missing keel panels that are at least part to blame for your worries. But just so you know, yes we indeed have the same exact transmission. When my transmission started to go she would hesitate to engage in gear. At first I could overcome this hesitation simply by applying a little extra throttle. Eventually the delay turned into five to ten seconds. Finally, one day she refused to engage in forward gear at all. Reverse gear was never affected.

Resolving the problem was an extremely expensive nightmare. When Albin built these boats they basically installed the drive trains and then fiberglassed the topside mold to the bottom without any consideration for the idea that maybe, possibly someday someone may need to replace a transmission. The boat yard had to make two small precision cuts in the aft bunk above the v-drive (where the battery switches are located) to allow them to slide out the old transmission and slide in the new one. But first, before this could be accomplished, they had to build a very special support bracket to support the weight of the engine in order to detach the transmission because the forward motor mounts are actually on the transmission, not the engine. To make the job more difficult, our boats have no support under the engine because of the empty void of the keel that runs directly under the motor.

As far as replacement transmissions go, this was also a severe nightmare. The Velvet Drive 7000 was a short-lived bad experiment by Borg Warner so it was quickly discontinued. The Drive has almost twice the moving parts and is considerably longer than any of the competitor's transmissions designed for the same load. Replacing this transmission with a competitor proved to be virtually impossible. A shorter replacment transmission would have called for either moving the motor forward eight to ten inches or having a company fabricate a longer jack shaft to make the connection between the transmission and the V-Drive. I don't have the exact details but the longer jack-shaft proved to also not be an option (there is a scientific formula that engineers use to determine the maximum jack shaft length possible without losing functionality. The length needed with the longest replacement transmission that we could find was too long for physics to work correctly).

All of this left us with either three options- buy a brand new motor with transmission (I wish), try to rebuild my Velvet Drive 7000 or find a good working one somewhere in the country. The next problem was that we found out very quickly that due to the poor economy, all of the major suppliers of parts for the 7000 have gone out of business. There are a few companies around selling gaskets and a gear or two but no company that has a complete stock of all of the hundreds of moving parts inside these crazy gears. It took some time but eventually my transmission shop was able to find a lightly-used 7000 that he was able to strip down and replace any parts that needed replacing using brand new parts he was able to locate as well as some parts from my transmission that were still in pristine condition. In the end I was told that my boat may have just received the very last series 7000 available in the country in this new of a condition. Everything else that is out there seems to be transmissions with mystery parts with no way to know the origin or the condition of what lies inside.

John, I pray that your problem isn't transmission related because I'd hate to see anyone go through this same ordeal. I tend to block the exact figures out of my mind so that I don't get depressed about it but in the end the entire transmission replacement with new motor mounts and new transmission cooler including the fabrication of the support bracket as well as the fiberglass work in the cabin cost me somewhere between $10k and $15k to complete.

[jruesr]

Well, I do not know what to say about some parts of your investigation. My engine, transmission and both of my fuel tanks came out through the cockpit opening without cutting any fiberglass anywhere. Albin may have put things in the boat before the deck went on but either someone did some careful measurements in calculating the cockpit opening size or they were very lucky. These days I think its rare to find a boat where everything can come out without doing demolition.

We separated the transmission from the engine before removal. One of my friends took his engine and transmission out in one piece. The ladder had to come off which required some upholstery work inside the cabin. This was needed for access to the bolts for the ladder.

Also, long drive shafts were available last time I checked and are shown in the V-drive manual.

Well now I am even more hopeful about my problem just requiring some glass panels to cover the shaft inspection area. I am confident that this is going to work for me.

Thanks again

John

[Seaslug44]

And the diagnosis is... the OTHER fuel pump!

Very interesting (and hopefully good) news today from the boat yard. They were able to secure the time of a Cummins factory rep who also is one of my area's top Cummins mechanics. The Cummins guy took a test ride on my boat with all sorts of diagnostic factory gauges taking readings as the boat was under way. His diagnosis- a faulty fuel pump down below. Not the fuel pump on the engine that provides pressurized fuel to the injectors but another fuel pump on the boat. Basically, my engine has been starving of fuel. The ability to only obtain 2100 rpms max with absolutely no black smoke combined with confirmation that my throttle was fully opening made him suspect that this other fuel pump was the culprit. The pressure readings he obtained confirmed it. I wasn't along for the ride to ask questions but I will try to find out more details.

Does anyone know where this second fuel pump is located on our Albins? Is it between the Racor filter and the last chance filter on the engine?

Is this something that is normal for all 6BTA's as well as other diesels in our Albins or is my boat just a freak?

[Seaslug44]

Actually just learned that this pump is called the "Lift Pump". Motor can still run without it but can only run on whatever fuel the injector fuel pump is able to suck in. That explains why I can only gain 2100 rpms under load and no higher. Can't wait for the new lift pump to arrive and be installed.

[DougSea]

Actually just learned that this pump is called the "Lift Pump". Motor can still run without it but can only run on whatever fuel the injector fuel pump is able to suck in. That explains why I can only gain 2100 rpms under load and no higher. Can't wait for the new lift pump to arrive and be installed.

Sounds like you might get out of this relatively cheap! And it's nice to know your motor checked out ok with the expert. Good luck with the new pump!