Engine Surges on Suzuki DF140

[Gene4488]

I'm at wits end and I can't afford to keep replacing parts.
I have a 2003 Suzuki DF140 4stroke with less than 80 hours on it. I was having problems with the engine bogging down when I tried to punch it.

Took it to an authorized Suzuki mechanic, in hopes of getting repairs done accurately. After spending $1,000 to replace Fuel Pumps, fuel filters and clean injectors, now I'm having a different problem.

If running the engine at 4K RPM or so, the RPM's start dropping to about 3600 and continues to jump back and forth. The engine does not stall and runs perfect at idle.

One thing I noticed is that every time the engine RPM's drop, the fuel needle indicates empty, then jumps back when the engine regains proper RPM's.

Does anyone have any suggestions? Ideas?
Please Help!!!

[Tallmantwo]

Can't explain the fuel gague but remindes me of the time when I used 5 gallon fuel tanks and would forget to open the vent on the gas cap. Iwould look at the pump up rubber bulb and it would be sucked closed. I have a 140 with 280 hours on it on a 03 Triumph 210. Mel, High Point NC

[Gene4488]

Thanks for the info. I will check to see where the fuel tank has its breather.

I have a 2001 Logic 210CC
If anyone has checked this before, can anyone let me know where to look?

[Tallmantwo]

also I have some kind of insect to fill any hole in my boat and/or motor with mud, kind of like a mud dobber. I think itis some kind of spider.


Mel

[Putershark]

I would start looking at...

• Possible loose ground wires at the engine block (does not take much a voltage drop to confuse any ECU) would just take any grounding wires and clean under them and re-secure all on the engine block. Matter of fact, you drop below 10.5 volts and many ECU's drop into a limp home mode with no timing advance curves and these engines start to run very poor.
• Clean and re-secure all battery connections.
• If you have a A/B battery switch, make sure all connections to the back of the switch are secure and use locking washers to help prevent them from getting loose again.
• Engine charging system output at the higher RPM's.
• Spark plug wires breaking down under stress or arching past the plug boots to the block. 10 ohms or higher resistance on any plug wire is asking for problems.
• Fuel injector leads clean and secure.
• Ignition switch wires all nice and tight and no vague spots (hard to explain) when moving the key from the start to the run positions.
• "Very Carefully and in very small amounts" spray some throttle body cleaner while the engine is running and warm and see if you can find a vacuum leak in a manifold or vacuum line. The engine will increase either increase in speed or stumble pending on the size and type of the leak. What you are looking for is a "change" in engine RPM (up or down) from it's normal idle speed.

I am sure others will cook up some other places to look to go

[Gene4488]

I think I got it. Seems like the mechanic routed a gas line incorrectly and it was kinked, restricting fuel flow.
I rerouted it and will test it this week.

Thanks for all your help.