Mahe 36: Low power in gear

[Rufduck]

Help please.
D1-30 130S in Mahe. About 2400 hrs for both engines. Everything fine six weeks ago (noticed that WOT was perhaps 2900 on port engine but it was only a casual observation when I applied a periodic burst of full power) WOT gave 3000+ in neutral and about the same when stationary in gear for stbd and perhaps 2900/3000 port.
Now sitting in Nanaimo, BC with the port engine turning 3000+ in neutral but only 21-2200 in gear.
Changed fuel filter, no change. Dove and Cleaned prop (small amount of green hair) and no trash in prop, no change. Engine/drive fluids are Okay and drive oil doesn’t smell burned. If it was air filter, presume it wouldn’t turn 3000+. Noticed that off and in gear, that the prop will turn with some resistance but not like it is turning the engine but I don’t know the inner workings of the drive to know if it’s normal. Wish I had thought to compare to good side but was cold. Finally, when wife was doing the run up and retarded throttle to dead slow and in gear the drive made a lot clattering and shaking. Almost like too much gear lash or a bad u-joint in std auto transmission (I may be doing a bit of imagining at this point).
Apparently Nanaimo doesn’t have a wide enough travel lift nor a VP service center. Been working toward this trip since March but I’m not happy pushing into tidal rapids in narrow passages with only one engine.
What am I missing? Suggestions? Anyone? (Indistinct muttering not appropriate to print)...
Martyn Adams

[LeeV]

Martyn,

Sorry to hear what’s happening. I’m hoping Cotemar is still listening in on the Mahe forum; if not, you’ll find him on the Helia group, and send him a pm. Very nice guy, owned a Mahe and knows more about the FP boats than FP I think!

Best regards,
Lee

[rabbi]

Originally Posted by Rufduck

Help please.
D1-30 130S in Mahe. About 2400 hrs for both engines. Everything fine six weeks ago (noticed that WOT was perhaps 2900 on port engine but it was only a casual observation when I applied a periodic burst of full power) WOT gave 3000+ in neutral and about the same when stationary in gear for stbd and perhaps 2900/3000 port.
Now sitting in Nanaimo, BC with the port engine turning 3000+ in neutral but only 21-2200 in gear.
Changed fuel filter, no change. Dove and Cleaned prop (small amount of green hair) and no trash in prop, no change. Engine/drive fluids are Okay and drive oil doesn’t smell burned. If it was air filter, presume it wouldn’t turn 3000+. Noticed that off and in gear, that the prop will turn with some resistance but not like it is turning the engine but I don’t know the inner workings of the drive to know if it’s normal. Wish I had thought to compare to good side but was cold. Finally, when wife was doing the run up and retarded throttle to dead slow and in gear the drive made a lot clattering and shaking. Almost like too much gear lash or a bad u-joint in std auto transmission (I may be doing a bit of imagining at this point).
Apparently Nanaimo doesn’t have a wide enough travel lift nor a VP service center. Been working toward this trip since March but I’m not happy pushing into tidal rapids in narrow passages with only one engine.
What am I missing? Suggestions? Anyone? (Indistinct muttering not appropriate to print)...
Martyn Adams

What puzzles me is the vibration. Sounds more like trouble in the SD. I can turn my props with one finger easily. If theres much more resistance or mechanical noise when spinning then something is wrong here.


I'm no diesel expert but three ideas spring to my mind:
Air filter. Just remove it temporarily and see if it makes a difference.

Exhaust mixing elbow could be blocked by soot. Take off and check.

The nasty one: Diesel bug. We had the similar issues (low rpm on WOT) due to reduced diesel flow when the pickup in the tank was partially blocked. Nasty thing, you can find my post about it here on CF.
You can remove the hoses from the pickup lines and remove the pickups from tank through the inspection port in the cockpit. If there is slime on the pickup lines you have a nasty bug.
Good thing is it takes just two hours to get the tank out in the mahe - unless its a full tank.

Good luck!

[cuffy]

Rabbi

How did you get the "bulkhead" in the cabin out to access the tank?
Was it just glued or were there fixings?

Cuffy

[VanIsle]

Martyn, please pm me. I am nearby. Stones marina in Nanaimo can lift your boat. They've lifted my Mahe a few times.
Gary

[rabbi]

Originally Posted by cuffy

Rabbi

How did you get the "bulkhead" in the cabin out to access the tank?
Was it just glued or were there fixings?

Cuffy

If you are talking about the wooden panel on the inner side of the bed that was screwed in place. A few screws at the bottom only.
Once unscrewed it can be worked out carefully as its a tight fit.

[rabbi]

Found the posts about my diesel bug in the Mahe engine thread starting here. A few posts down is a nice picture of the bug.


But before you start removing the tank make sure this is really the cause of any problems. Its about two hours work out and two hours back in, depending on how much diesel you have left in the tank.
But its a dirty job where you risk smell and dirt in the cabin and stains & scratches around the stairs. So don't do this unless you have to.