speeding up

[401kfishing]

my suzuki df300 is speeding up by itself then coming back down to the rpm that im running also the guage on that engine is not showing any info on the engine like temp etc what could be causing this. it also has a ruff idle.

[401kfishing]

speeding up

guys nobody have an idea about whats going on

[Harper2]

Well, you're asking about three different questions, and really need to be a bit more specific about each one of them. What RPMs on the "speedup," under what conditions? To what kind of gauge are you referring...an SMIS gauge? How did you hook it up? Have you performed the setup. or did an installler set it up, and if someone else did it, was it explained to you. Have you read the gauge manual, and understand how the gauge and various settings work, so that a discussion of the problem will be meaningful to you? Describe your "ruff idle." Does the motor stumble upon acceleration? What's the idle RPM? Does it run smoothly at RPM, except for the RPM increase, and does the RPM increase happen repeatedly, like a constant surge, or just once in awhile, or what? How old is the motor? What year? Is it under warranty? All these things will need to be taken into consideration, and we will need to know at least a few of these things before even attempting to answer. Give us a hand here, and we'll try to address your problems one by one.

[401kfishing]

speedin up

when im running at 3500 rpm it speeds up to like 4500 rpm for about 10 seconds then comes back down. the motor is a 2007 df300 the gauge is the smis gauge

[401kfishing]

everything was set up by the dealer

[Moonlighter]

Has the gauge just started to do that, or has it always been that way since installed by the dealer?

Does it turn on at all, or just a totally blank, unresponsive screen? When did it start doing that? Had anything been changed at around that time - for example, a recent service? Battery replaced?

Check that the connection from the gauge to the Network T piece behind the dash is plugged in correctly. Unplug, check, and reconnect. If it is completely dead, and you have 2 gauges, you could swap connectors and see what happens. Sometimes a T piece will fail, if you swap and it works on the other T piece you will identify that as the problem.

You need to give us some info and do some checks along these lines.

I take it that you have twins on the boat? Other engine OK?

Changed filters lately on either engine or on fuel lines?

Any engine alarms or warning codes happening?

Re the rough idle, is it like the engine is missing? Have you pulled the plugs to have a look at them? At 3500 rpm, are you getting those revs at similar throttle opening as the other engine?

These motors, above almost everything else, need 2 things, and these are often the first places to look when there are problems:

1. Good, clean, fresh fuel supply.
It is imperative that you have a water separating fuel filter (eg like a RACOR) in line between the tank and primer bulb. The ones that are in the engine bay are not enough by themselves.
Missing, stalling and poor running can be due to blocked filters, vent problems (eg wasp nests blocking vents or faulty anti-siphon valves on the fuel tank outlet.

2. Good, solid 12V power supply. A dodgy battery or battery switch, poor or dirty battery connections, corroded wiring, all cause poor running. Most of these are extremely easy to check and maintain so that they do not occur. Definitely remove the battery connections, clean with a wire brush, and replace them carefully. Check the cables near the lugs while you are there, give them a bend and if they feel crunchy, you have a problem. Get rid of any wing nuts on battery terminals and replace with proper hexhead nuts and tighten with a spanner

So have a look at these kinds of things first. Most are simple and easy to do checks.

If you don't feel comfortable doing those kinds of things, that's fine. Your best course of action then is to take it back to the dealer. But, the same as here, you need to give the dealer the full story, very bit of info about what is happening, when and how frequently it happens, and any changes made to the boat recently that might even remotely be related.

Similarly, if the engine is under warranty, just do the simple checks like battery and fuel filters and vents, if that doesn't sort it out, back to the dealer you go!