Engine malfunction

Hoye · Nov 13, 2010

I have a 1997 / 1996 model 425 Magnum (Norwegian model).

It (the engine) has suddenly started to run quite bad. It starts perfect, on idle it runs so nice, but when I give more trottle then it starts running really bad. To me it seems like there are either something wrong with the carburator or the ignition. It is not possible to get it up on high rpm.

I have tried to disconnect the black cable into the speed limiter, but that had no effect.

The carburator has been checked and should be in perfect condition.

The intake have been checked and are without any cracks etc.

New spark plug and cable installed.

Airfilter cleaned.

Valve clearance have been checked and seems to be OK.

Fuel pump seems to work OK - it pumps quite a bit of fuel..

I would be so glad for some good advices!!!:thinkerg:

Bruce! · Nov 13, 2010

Welcome to the board!:wavey:

4getful2 · Nov 13, 2010

and the lobes on the came were fine??

Hoye · Nov 14, 2010

Yes, it looks like the cam and valves etc was OK.

tt425 · Nov 15, 2010

Check the ETC(electronic throttle control) switch. It may need to be adjusted or replaced. Thanks

Hoye · Nov 15, 2010

How can I easiest check the ETC?

Hoye · Nov 17, 2010

It was nice and clean!

tt425 · Nov 17, 2010

Check the exhaust system it may be plugged or restricted.

tt425 · Nov 17, 2010

other things to check :
carburetor vacum slide sticking/diaphragm damaged (check this first)
ignition timing
spark plug fouled/weak spark
obstruction in air intake
air box cracked
incorrect or restricted carb jets
Hope this information will help

Hoye · Nov 20, 2010

Hi, Thanks for good advices.

I have cheked a lot of things today. Checked selveral electrical connections, exhaust, Air intake etc. When I put it all together it workd perfectly!!!

The only problem is that I blow the variator drivebelt when I testet it!! (

Engine malfunction

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