Engine Issue - Things to Check?

Stemar

Stemar

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We took our first rip out of the Harbour on Jazzcat over the last couple of days. Nothing too adventurous, just up to the Folly for dinner, then on to Newport for Riverfest. Both engines performed faultlessly when working, but the starboard one persistently stalled when slowed to idle approaching the pontoon. It would start again given several seconds of churning and lots of welly, but was most unwilling to participate in the slow speed manoeuvres involved in coming alongside.

Any suggestions? The primary filters have been changed and this seems to be too recent a thing to be directly related.
 
will it stall only when engaged, or stall also in idle gbox in N?

and is idle speed in N of both engines identical?
batteries charged by this engine alternator? good condition?
easy answer is idle slipped too low, only it doesn't really happen just like that...
 
Stop on slow speed, that sounds like if I does not get enough fuel.
Check if there is air somewhere in the fuel system. Maybe you did not bleed good enough when you changed filter.
Check also if there is water in the diesel.
 
Stemar said:
We took our first rip out of the Harbour on Jazzcat over the last couple of days. Nothing too adventurous, just up to the Folly for dinner, then on to Newport for Riverfest. Both engines performed faultlessly when working, but the starboard one persistently stalled when slowed to idle approaching the pontoon. It would start again given several seconds of churning and lots of welly, but was most unwilling to participate in the slow speed manoeuvres involved in coming alongside.

Any suggestions? The primary filters have been changed and this seems to be too recent a thing to be directly related.
Click to expand...
Fuel, lack of
 
It's recent fuel, idle sounds right, the same as the other engine (no rev counters) and it's the same revs in gear and neutral.

I would have expected diesel bug or any other sort of blockage to have more effect when the engine's working hard, as there aren't any idle jets on a Beta 20!

Am I right in thinking that, if air can get in, fuel will also get out, so I should check for any signs of leakage? Would it also make sense for a tiny air leak to get swallowed up when the engine's working, but matter more at idle?
 
Stemar said:
........Am I right in thinking that, if air can get in, fuel will also get out, so I should check for any signs of leakage? Would it also make sense for a tiny air leak to get swallowed up when the engine's working, but matter more at idle?
Click to expand...

No that isn't right. Surface tension can stop liquid escaping through a gap where air can get in. That's why these problems can be very hard to track down!

I'll agree on the high revs/high fuel flow hiding the problem.
 
If your using CAV type filters, check for small dinks on the sides. I had one and it just distorted the filter enough that the lower seal just let in tiny air bubbles.
 
I agree with Penberth3. I have had no sign of leaking of diesel, but the engine stoped. When I bled the system I found out that there were air there.
I would do it in this order since you recently changed filter:
Check water separation if you have any.
Bleed the system.
Bleed again if it does not work.
Pump up diesel from the bottom of the tank and see if you have water or bugs there.
 
You're not getting enough fuel at low engine speed.
You either have a partial blockage somewhere or an air leak into the fuel system.

Partial blockage is likely to be caused by diesel bug - check the CAV filter - is it black with the bug?

Check for air leak into fuel system by bleeding again - do you get any air out? Perhaps a seal was missed or damaged during re-assembly after primary filter change?
 
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