DF50 2008 remote - just started cycling

[mike.floutier]

Hi,

I recently bought a MacGregor 26M with a DF50 2008 remote.

I've had it on a mooring for a couple of months and all was well with the outboard until yesterday when it started cycling. Not sure what the revs were as I've not set up the SMIS yet, but not fast.

Leading up to this first cycling event:

1. The motor was warmed up and running fine.
2. When we were out in the bay and I wanted to go under sail alone so I switched off the motor (with the key) forgetting that it was in gear and running forward - low speed.
3. We noticed that the motor was still apparently running. I then removed the kill cord. The motor still seemed to be running.
4. Then I noticed the power lever was in gear and powering forward so I returned it to neutral and the motor stopped.
5. I then tried to raise the motor with the TTL but it wouldn't move.
6. On going below to check fuses etc I noticed that one of us had inadvertently knocked the engine electric supply switch slightly.
7. I switched it on and was able to raise the motor ok. Didn't think any further at this stage.
8. When we had finished sailing and were returning to our harbour I lowered the motor and started it ok; running at idle in neutral until needed.
9. We started motoring in due course, again at low speed, with no issues.
10. We were then overtaken by a fast RIB and, for fun, pushed the throttle pretty far open for a couple of seconds and then back to 5 knots power as before.
11. Very soon the motor changed speed. At first I thought my friend had nudged the throttle accidentally but he hadn't and the cycling had clearly begun at this stage. The cycling carried on until we (thankfully) reached out mooring. At this stage we put the motor into neutral and idle and the cycling stopped i.e.. it idled cleanly.
12. I left it running whilst we tidied up the boat and, before shutting down I tried opening the throttle whilst in neutral. Again the cycling re-started.

Obviously I'd like to sort out the problem before going out again and wondered if anyone could help with this.

Many thanks!

Mike

PS. I may have mis-remembered the business about the motor still running after removing the kill cord BUT we both confirmed that it was and my friend is an experienced sailor. Seems odd, could it relate to the interrupted battery power supply?

[Moonlighter]

Can you please describe this"cycling" for me?

Are you meaning that the engine is surging? Or is it misfiring? Any alarms going off?

The more fully you can describe what the engine is doing the better someone may be able to help you.

Some comments follow though that may or may not be relevant to what is happening:

These engines have over-rev limiters that protect them from destroying themselves -

First, they have a limiter that prevents over-revving when the engine is in gear. Usually they cut in at about 6400rpm, depending on model. Its possible that your sudden acceleration may have caused the engine to hit the limiter. I seem to recall that to reset it you have to return to neutral for several seconds, otherwise the limiter is still activated and the engine wont rev up to cruise speed.

Secondly, they have a limiter that prevents over-revving in neutral. Its called the neutral throttle switch. This limits neutral revs to about 3000-3500rpm. What it does is to interrupt spark and fuel delivery and retards timing when the engine is revved too hard in neutral.

So, when you had the engine running in neutral and revved it up, this may well have been the cause of the symptoms you described as "cycling".

This switch is located on the engine gear linkages under the cowl on the starboard side. They can get dislodged or break or otherwise fail. If the symptoms continue it may be worth checking this switch. Not an expensive thing to replace if necessary.

I would also suggest you check simple things like fuel supply and in that regard, it would be a good idea to change your water separating filter element and when you do, check for any water in the fuel.

And, undo, clean and retighten all battery connections and associated switches, these engines need a good solid 12v supply. Check battery charge too.

Then test it again and see if it runs ok.

Let us know how you go.

[mike.floutier]

Many thanks Moonlighter,

Yes I did mean surging; NOT mis-firing. It's as if the motor was running fine but someone was slightly decreasing the throttle setting for a second or two and then increasing it. It cycles through this process again and again. It's quite similar to when my Volvo diesel car needed its fuel filter changed and I had left it too long - ie fuel starvation.

I'm not yet able to check for engine warnings as instead of the rev counter/warning lights dial, that the manual led me to expect, the boat is fitted with a Suzuki SMIS dial that needs to be programmed with what is displayed/warnings/sounds etc. As its new to me and the motor was absolutely fine I had not got around to it.

I plan to visit the boat on the mooring tomorrow morning. I will program the SMIS and then run the motor again to see what's going on.

As far as I can tell there's no water separator in the engine, nor in the tank > engine fuel line. Although the manual does mention a vapor trap in the high pressure fuel pump.

Looking through the service history - previous owner kept all documents - a quick service was done in May this year. This included engine oil/filter, gear oil changes plus "clean fuel filter" - assume this is low pressure.

Prior to this the most recent service was in May 2012 - don't think boat got too much usage. On this service: water pump kit, gear oil change only plus spark plugs. Also mentioned appears to be "remove and clean fuel filter refit/ fit new filter assy and clean (drain?) off vapor trap prime with clean fuel". Hard to read the handwriting

Not sure what this last bit means. Does it all relate to the low pressure filter? I guess it would make more sense to drain a vapor trap rather than clean it.

Will report back after my boat visit. Am tempted to leave this until boat is out of water in 3 weeks but we've only had two months of the season, having had a late start, so I'd like to get to sail a bit before the winter.

Thanks again for you time/help, it's much appreciated!

[Moonlighter]

Ok it sounds like the previous service included cleaning the fuel filter and related components in the motor. Possibly some hints there that fuel has been an issue in the past?

Maybe the tank is contaminated? Does it run off a portable tank or built-in? Are you sure that the duel is fresh and hasnt been sitting in there for years? That will also do bad things to the way the engine runs.

The surging as youve now described is often a symptom of a dirty fuel system and/or water in the fuel - the two often go together, unfortunately. You may well need the system cleaned out again if that is the case.

Your very next job should then be to buy and install a Racor style water separating fuel filter between the fuel tank and the primer bulb. They are really absolutely essential for keeping water and dirt out of the engine's fuel system. Cannot over-emphasise how important this is.

Hint: when you've got it all installed, take the filter element off and fill it as full as you can with fuel carefully, then screw it back on. This makes the job of priming the system far easier!

My money now is on dirty/watery/stale fuel.

[mike.floutier]

Many thanks Moonlighter, I will follow your advice and get a Racor style filter/separator.

Regarding the fuel, I bought a new high quality 6 gallon tank just before launching the boat 2 months ago and am using the fresh (from the pump) fuel I bought at the time, I've used about half of the 5 gallons I put in, so unless it can go bad in two months this shouldn't be the cause. How long does fuel last before degrading?

I'm guessing that when I get the low pressure filter unit off tomorrow there should be some obvious signs of dirt/water although if the May 16 service did in fact clean that unit then the evidence may well be further downstream; ie high pressure unit/injectors.

Anyway, will report back ASAP.

[Moonlighter]

Ok, thats good, fuel should be OK with the new tank.

Just a thought ..... The new tank ..... Breather?? You did open it? ........ Wouldnt be the first time someone (me included) left the breather closed and starved the engine of fuel..... Especially happens when rpm's increased ..... ??

I have also been hearing bad stories about the EPA requirements for new portable tanks in the US causing fuel starvation issues due to their "closed" systems. I do not know much more as We dont get those tanks here in Aus, so maybe thats an issue to consider or investigate further too? You could try opening/loosening the filler cap a touch so it can breathe and see what that does....

[mike.floutier]

Many thanks, I'll try that.

[mike.floutier]

Many thanks for all your help Moonlighter.

Looking at the manual there is a rev-limiter built in to the ECM which limits the revs to 3000 if either; 1. The "in gear" limit of 6700rpm (7000 prior to mid 2004) has been exceeded - triggering a caution, or 2. Revs exceed 3000 in neutral.

Having checked out all the fuel starvation suggestions, I tried gradually increasing the revs, in neutral, having got the SMIS programmed so I could see how high I was revving.

All ran very smoothly until just about to hit 3000rpm. At this stage the "fuel starvation" thingy started happening - surging around 2900-3000rpm. I had read, in the manual, that the rev limiting strategy was implemented simply using fuel injection commands.

This explained the scenario I have experienced. Indeed I could push the throttle as high as I liked in neutral but the revs remained as above until I lowered it under the 3000 level, at which stage the engine ran smoothly again.

I should have read the manual more carefully and programmed the SMIS from day 1.

Thanks again for all your help, at least I now know my way around the engine a bit.

[2014DF25ARS]

FYI, on my DF25A the SMIS "gauge" will display a "REV LIMIT" popup message when I hit the 6200 RPM rev limit. I've never experienced the neutral rev limit, so I'm not sure if the same happens.

There is an option in the SMIS configuration to display "Engine Warnings". (There's a currently-active thread on this subject in this forum.) I'm not sure what that option controls, but I have it enabled on my SMIS display.

[mike.floutier]

Thanks 2014, I read through Grant's excellent article and as far as I can see the SMIS will present cautions/warnings BUT this does depend on the engine transmitting the relevant data AND as he mentions only later engines do this.

I guess the best way to confirm whether or not warnings are transmitted is to provoke the engine to generate a warning.

The most sensible one to provoke I guess would be over-revving so, now I've got the SMIS up and running, I'll try over-revving and see what happens.

That is unless anyone happens to know if a 2008 DF50 will transmit warnings digitally.

[mike.floutier]

Hi, I just wanted to say a big thank you to Moonlighter et al for all your help and encouragement, before I disappear off into the ether.

With your help I've become passably familiar with my outboard and confident enough to tackle basic tasks - eg I changed my spark plugs and low pressure fuel filter on my mooring the other day.

It's also so reassuring to know that I can return for more help as needed.

This all greatly improves the overall boating experience as one doesn't feel alone.

Thanks again!

[Moonlighter]

No problems!

Btw, I am almost certain that your engine will send fault codes and they will display on the SMIS displays.

The safest way to test this, if you can be patient, is to wait for the next 100hr service/oil change alert. This will start a beeping noise and pop up a reminder, if I recall correctly.