Beta 35 won't rev, hunts just over tickover.

[GHA]

All was fine then on a passage yesterday the engine wouldn't drive much over tickover, seemed OK in neutral then just got worse. Got into an anchorage OK, (Sagres) changed both filters. Bled then seemed to rev in neutral to full revs. Tried to move & same thing. Now bypassed primary filter (nearest tank) so day tank gravity feeds straight to secondary filter. If I undo bleed screw top of secondary filter on engine fuel comes out, presumable under gravity, slacken bleed screw on injector seems like lots clean fuel coming out when pumping lift pump. Engine will start but won't rev in neutral, revs up a little & hunts a bit.
Stumped now - any ideas? Gotta be fuel right?

edit. so took off the banjo connected to the injector pump, spurt spurt fuel coming out when pumping the manual lever on the lift pump. Same thing with the engine, will start but won't rev.

Gusting 30Kts straight into this anchorage monday morning... could do without this....

 

[MoodySabre]

Undo the fuel filler cap - maybe the breather has blocked.
Has the air filter collapsed?

 

[GHA]

Undo the fuel filler cap - maybe the breather has blocked.
Has the air filter collapsed?

air filter fine, changed it. Will try with filter off. Fuel seems to be getting to inject ok...

 

[V1701]

Any 12v pump? Connections?

 

[MoodySabre]

air filter fine, changed it. Will try with filter off. Fuel seems to be getting to inject ok...

Fuel will get through very slowly but not enough for revs and power. Try it with cap off (been there....).

 

[GHA]

Fuel will get through very slowly but not enough for revs and power. Try it with cap off (been there....).

just took fuel pipe off banjo into injector pump, big spurt of diesel, like squeezing a spot. Breather in day tank fine , checked that.

 

[Wansworth]

Nothing round the prop?

 

[GHA]

Nothing round the prop?

won't rev in neutral.

 

[GHA]

I`ve a facet type pump, would it harm the lift pump if I connected that to the input? Grasping at straws a bit, can feel a day & night hove too at sea coming on

 

[Boater Sam]

Water in fuel?

 

[ean_p]

Are you certain fuel is getting to the HP pump assembly?
If so consider;
Check the linkage and levers on HP pump assembly, and if possibly disconnect and work by hand, especially the stop lever/ mechanism
Check that you are getting 'spill back' return.
Disconnect as close to pump / injectors as possible and collect spill back into separate container for a short while to prove that flow is OK .

 

[GHA]

Are you certain fuel is getting to the HP pump assembly?
If so consider;
Check the linkage and levers on HP pump assembly, and if possibly disconnect and work by hand, especially the stop lever/ mechanism
Check that you are getting 'spill back' return.
Disconnect as close to pump / injectors as possible and collect spill back into separate container for a short while to prove that flow is OK .

Stop works by hand, throttle seems OK, looks right, problem has been gradual. This look OK? Fuel return to tank

https://imgur.com/4Y2gMQ7

 

[GHA]

Water in fuel?

day tank refilled from diesel bought from busy marina week or so ago, should be ok-

 

[Boater Sam]

That fuel looks odd to me, red or white?
Its rained a lot, could you have leak into day tank or condensation?

 

[GHA]

That fuel looks odd to me, red or white?
Its rained a lot, could you have leak into day tank or condensation?

looks fine in the real world, problem is intermittent as well, just revved to full, tried bit reverse & faded then faded in neutral as well. Don't think it's the fuel. It never rains here.

 

[ean_p]

so this is the current state of affairs;
Was all running ok
Then struggled to rev 'high' while in gear but would rev 'high' while in neutral.
Then struggled to rev 'high' while in neutral. In all cases it started as per normal?
Now it still struggles to rev 'high' either in gear or in neutral but starts normally.
It has ( how many times ?) recently rev'd high (in neutral or in gear?) which then faded away ( after how long?)
What had you done on the engine or related ancillarys just prior to this/ these high revving episodes?
Have these episodes been here all the while or have they just started?

 

[GHA]

so this is the current state of affairs;
Was all running ok
Then struggled to rev 'high' while in gear but would rev 'high' while in neutral.
Then struggled to rev 'high' while in neutral. In all cases it started as per normal?
Now it still struggles to rev 'high' either in gear or in neutral but starts normally.
It has ( how many times ?) recently rev'd high (in neutral or in gear?) which then faded away ( after how long?)
What had you done on the engine or related ancillarys just prior to this/ these high revving episodes?
Have these episodes been here all the while or have they just started?

After rerouting the return to film, it would rev to close to full, tried reverse, faded, after that won't rev much over tickover.
Problem started yesterday when I notice it gradually fade. Would run high in neutral so I suspected net round the prop but prop free, then wouldn't rev high in neutral either. Then got windy so sailed to anchorage & got enough drive low revs to get the hook down. Changed both filters today & revved high in neutral, ran for a bit & problem came back. Seems like if left for a while it will rev high in neutral, maybe... Don't think it's overheating, looks usual >

Does feel like its getting fuel starved, but seems to be fuel getting as far as the injector pump. And nice rolly anchorage just to help
Revving up to 2200 ish here, full more like 2800

thanks!!

https://imgur.com/iimOgXA

 

[ean_p]

Mmmm from what you describe it sounds like the fuel is being 'held' back by a blockage or 'airlock' to the extent that sufficient gets through to start and tick over but insufficient to supply increased demand as when you have 'disturbed' the fuel system you get a short period of relatively normal running. It would be good if you could supply filtered fuel direct to the outlet of the secondary filter housing point as a proof to see if the engine would run when given sufficient fuel.

not sure what this means..'After rerouting the return to film'.......'film'?

 

[greeny]

Mmmm from what you describe it sounds like the fuel is being 'held' back by a blockage or 'airlock' to the extent that sufficient gets through to start and tick over but insufficient to supply increased demand as when you have 'disturbed' the fuel system you get a short period of relatively normal running. It would be good if you could supply filtered fuel direct to the outlet of the secondary filter housing point as a proof to see if the engine would run when given sufficient fuel.

not sure what this means..'After rerouting the return to film'.......'film'?

To film it going into the bucket/ water bottle or whatever it is. I think.

 

[Bodach na mara]

Simple thought, is the throttle link working OK? I had a similar problem with the screw clamping the inner wire of the Bowden cable allowing it to slip.