DF 25 A Problem 3000rpm

[gsindel]

Hello

I have 2 Suzuki DF25A outboards. Engine serial nod Port: 02504F-512990 Starboard: 02504F-512987. They are about 1yr old and have done 220hours.

Some months ago we had a problem with the port engine not running properly over 3000 rpm. I would slow down and sometimes stop but would restart. This would happen only when running under load and sometime took a few minutes to occur. The mechanics changed just about everything over to no avail.The vapour separator was then taken apart and found to have salt crystals in it. It was cleaned out and everything ran fine. As the vapour separator is a non serviceable item I got a new one and this was replaced after 100 hours, all fine, A few tens of hours later a similar problem occurred on the port engine and then also started happening on the starboard engine. The problem is similar but not as severe. If you run the engines above 3000 (say 3800) after 30 seconds the engine cuts back (as if you lifted the throttle), if you dethrottle to 3000 it then continues to run fine. Its sounds like fuel starvation Both engines now behave identically. We examined the port engine vapour separator but this was clean. There a small amount of debris the high pressure fuel filter. We have the computer diagnostics kit and no cautions are were observed in all cases.
I aswell dont think is the 3000 rpm safety cut-out, it sounds completely different when it eould cut-out at 2000rpm in neutral.

The installation is a bit odd. This is a sailing catamaran but the engines come of the hull and run in an engine room rather than free air. The inlet of the engine is trunked into a separate airbox as we had a problem with the exhaust choking the engine when idling.

So any ideeas?

We are currently in the Maldives.

Any ideas.

In desperation

[2014DF25ARS]

I posted a few days ago about the same symptoms on my 1 year old DF25A. You could search for that post from me. My engine quit running on one outing and wouldn't restart. Found a lot of water in the fuel filter, but also found that the check valves in my primer bulb had failed. One valve had popped loose in the bulb, and the other seemed to be stuck shut... I replaced the bulb, and that's when I began to experience your symptoms. Would run at WOT about 30 seconds and then stall down to an idle. I would wait a minute, then could run up again for another 30 seconds. After about a half hour messing with things, I realized I had installed the primer bulb backwards! I suppose the valves in the bulb were severely restricting fuel flow, but after a minute or so enough fuel would make it though the bulb to run for another 30 secs.

I doubt your primer bulb is backwards, unless you've been working on the fuel lines lately. But given my experience, I would question those valves in your primer bulb. In my case, I could feel the loose valve in the bulb when I squeezed it. You might play with your bulb just to ensure it is working/pumping as expected. You should also look at the ball valves where the fuel line attaches to the tank, assuming you are using Suzuki's quick-release tank fitting.

[gsindel]

Thx for the reply
Im quite sure there is no issue with the primerpump because we bypass the system and still had the same issue.
We have a water separator in line and show no water. Aswell is a mystery how saltwater came in the fuel vapor saporator without any sign in the fuel/water separator...?? . The only guess is that somehow it must get suck back from the overflow hose from the vapor separator ... in dubios condition, the outlet of the hose is sometime in the water. We changet that of course.
So we still have the fuel starvation issue at 3000RPM on both engine....
regards