Engine suddenly loses power

[gaelforce]

For reference

Honda BF50 suddenly loses power, only goes forward or reverses at idle revs. Continues to tick over but won't increase revs past idling.
Lock pin on throttle arm disconnected refix washers use wire as cotter pin to fix

[Miss Guided]

My guess would be fuel starvation/contamination. Check filters and the journey of the fuel from the tank to the cylinder(s).

MG x

[TmMorris]

I think that's probably the first starting point. Work all the way back from the injectors to the tank, cleaning filters, flushing lines. Best guess would be that it's not any crud near an injector as the engine would Rev but be rough but that there may be some crud in the main system that is able to move and block the bulk of the fuel feed.

Easiest thing might be to replace the filter and borrow someone else's tank and line to see if that solves the issue. Then test with your tank and line to see if it returns etc.

If you can then rule out a physical reason for fuel starvation it may then be time to contemplate an electronic reason. At that point Is start with testing the fuel pump but after that I would be beginning to contemplate taking it to a chappie who can test gubbins like the ECU etc.

[Jon Tallis]

When you say "won't go past idle" is the engine trying to increase revs and failing (missing, spluttering etc) or just refusing to increase revs.
If the former, I'd be going with the previous responses and having a good look at the fuel system. Also check that if the ignition timing is advanced mechanically with the throttle, that that is actually happening.
If the engine is just refusing to increase revs then I'd be doing some diagnostics on the ECU to confirm it isn't going into some form of limp mode (but TBH I'd expect more than idle revs even in limp mode). Is your cooling water OK? Engine not overheating?

[paintman]

I stand to be corrected but I suspect the 'For reference' comment at the start of the OP's post is that the information is a 'heads up' for an issue they've found on that particular engine & the fix.

[Jon Tallis]

Originally Posted by paintman

I stand to be corrected but I suspect the 'For reference' comment at the start of the OP's post is that the information is a 'heads up' for an issue they've found on that particular engine & the fix.

Good point - I didn't quite understand the last sentence but now do [emoji106]