6LPA-STP Steam and RPM Question

[matty_mick]

I have a 2002 28 engine box model with a 6LPA-STP with less than 400 hours. It was used lightly by the previous owner until we purchased it in June…we run the boat frequently. We had Bayshore perform the valve cover job as the previous owner had not had the warranty work done. They also replaced zincs and timing belt during the service. Questions are as follows:

- I've read that this motor should turn 3900 under load at WOT. She will rev to the recommended 3900 in neutral but will only turn ~3700 @ WOT under load. Under load, there is no noticeable black smoke and engine temp holds steady. Boat came with a 19X19 LH prop. Curious if I should start at my local prop shop and have them recondition the prop to turn the recommended RPM or if I should be considering another cause?

-The boat has begun to emit white smoke upon startup as temps have fallen. I understand that this is normal and the smoke stops as the cylinders warm. What is concerning is the amount of steam that the boat emits from the exhaust at cruise. The steam has increased at water temps have fallen but was noticeable in the middle of August as well. I've included a picture of the steam, seen on the port side exhaust during a return trip last weekend. The engine is holding temperature below 180 and has not overheated. Curious if the steam is normal for these motors? Would a Rydlyme treatment or raw water impeller change possibly reduce the steam?

Any insight would be helpful!

Matt

[RobS]

See attached - No load rpm should be higher, did you stop at 3,900 or is that it? Did you check your tach for accuracy? Beede tachs are usually very close, Yanmar OEM's are junk, usually read low by over 100rpms..

Yes, white smoke is likely the normal un-burnt fuel during cold combustion different from the steam you are seeing at cruise, which in your pic looks pretty normal to me for a Yanmar. If steam is increasing with time could be due to higher exhaust temps from something in your cooling loop needing servicing and causing your raw water flow to be down.

[special k]

matt, i also have a2002 28te 6lpa-stp. mine runs as you describe and has for the 6 years i have owned it. i pay little attention to the accuracy of my tach and use it as a barometer for "my" engine. my rpms are similar to yours and my prop is the same. i feel my boat runs flawlessly achieving 22-24 knots at wot which shows as 37-3800 on my tach. i cruise at 18-20k with my tach showing 3200, my sweet spot. yes mine does produce steam which at first concerned me but engine temps stay under 180*. brand new raw water pump
i did have my 19 x 19 prop tuned and is smooth as silk.
i don't worry about the "absolute" accuracy of my tach only the constant gauge of my engine. absolute accuracy would only concern me if i were comparing to others or searching for a prop.

if my wot displays as 3700 and is actually 3900 i am not concerned. like stepping on an inaccurate scale daily i still notice any change in my weight if i use the same scale daily. repeatability remains constant.

good luck with your albin, they are awesome vessels. we cruise in comfort and also fish it hard....

cheers!

[furball]

I have a 2006 with the same setup. I have a Flowscan digital tach and it was significantly different from the Beede. I contacted Mack Boring to get the correct number of teeth on my flywheel. Mine has 117 teeth. I set the pins correctly on both and they are within 25rpms now. The Flowscan reads the same as the photo tach we checked it with.
As for the steam, looks normal to me.
My preheaters were replaced last year. They were drawing lots of voltage at cold startup but not getting hot. Made a big difference at startup.
I run a 19x18 prop. 3800-3900 at WOT. Completely loaded.
4200 at no load. I really hate doing that
Good luck,
John

[matty_mick]

Thanks for the replies fellas. Glad to hear the steam is normal. Regardless, I'm going to Rydlyme the raw water loop this weekend, as there is a good bit of back pressure in the intake hose on the intercooler. The original hose cracked on my 3rd trip out (thank you Rescue Tape.) The replacement hose is hard to the squeeze at cruise and pulled itself off the intake port last week. I imagine there is a good bit of scale buildup in the Intercooler after years of sitting idle with stagnant water in the loop.

Thanks for the RPM document Rob. Like Special K, I'm cruising @ 17-18.5 knots at 3200 depending on bottom growth and conditions. There is some prop vibration so I was going to have Black Dog recondition the prop this winter. Sounds like before I have them do so, I better make sure my tach is reading correctly.

Love the boat so far. Working out a lot of kinks after years of neglect by the previous owner. 4th boat I've owned but first inboard diesel…suffice to say, I have a lot to learn!

Hope to see you on the Chester John!

Matt

[RobS]

Thanks for the RPM document Rob

No problem, glad to help. You may be new to diesels but I can tell in what you've posted thus far you're on the right track to being a happy owner - Enjoy.

[chesapeake albin]

Hello,
Matt, Was that you I saw on the chester last weekend, I was heading into kent narrows in the green 28.

Travis

[furball]

Matt and Travis,
I'm in a blue hull 28 named Transition.
Been in the Chester most every weekend.
Slip at Castle Harbor marina.
I'll be out Sunday and Monday this week. Weather looks great.
If you see me, say hello.
I saw a green hull 28 go by last week but it didn't appear to have a name on the transom.
Seen a couple others in the last few weeks. Blue 31 out of Rock Hall, Canvasback I think.
Anyway, safe travels.
John

[chesapeake albin]

hello John,
It was you I saw, didn't want to get close as I thought you were fishing,
I do not have a name on there yet, Ill get to that this winter. I keep the boat in the Magothy now.

nice to meet you, it would be great to have some help getting some of these projects worked out

Travis
Dark green 28

[matty_mick]

Not sure it was me, Travis. I've been fishing the Chester a good bit recently, but headed south to St Michaels on Sunday with the family. I've seen several Albins in the area, as well as a nice 32+2. We named her OutNumbered (name made sense after we had our third kid!) Boat is at the KIYC on the northern most set of slips so chances are, if you've been through the narrows recently, you've seen her.

A personal thanks also to Rob. I've been pouring over several of your older posts….you've significantly shortened my learning curve!

[easyeee]

I have a 2003 same setup same problem had barnacles in the screens of the intercooler cleaned it out had radiator shop boil it out now its fine

[carolmarie]

My 2001 6LP-STE, runs exactly like yours and as Special K describes, also with a 19x19 prop. We have 975 hours and she has always run perfectly.
Don.

[matty_mick]

Wanted to provide a quick update. Made a set of adaptors similar to the set posted on this site, and Rydlymed the raw water loop this weekend. I did 30 minutes in forward, 30 minutes sit and then 30 in reverse. I then cycled a couple of buckets of water through in forward (changing water out as the dark water began to recycle), then ran it in forward on pure fresh water (maintaining bucket water level with fresh water hose, while allowing the outflow to run overboard.) Results were very impressive. I immediately noticed a significant improvement in the amount of water running out of exhaust. Significant reduction in the backpressure on the intercooler hose. I can now squeeze the hose while at cruise, whereas before it was as hard as a rock. Significant reduction in steam at cruise, and boat held temp at ~165 while running at full throttle for 5 minutes. Highly recommend the Rydlyme treatment for anyone who is experiencing temperature creep or pressure buildup in the hose running to intercooler....both are hallmark signs of scale buildup in the raw water loop.

Knocked out several big items on the list but still have additional projects to get OutNumbered in tip top shape. Part of the fun of ownership!!

M