Max speed of 50mph fourtrak


Hi - bought and 1994 F73 2.8 turbo diesel early this year which was always happy to cruise at 65 on duel carriage ways.

However last week pushed it to 70 (daring I know!) and it coughed (no smoke) and since then wont get past 50, unless downhill; and up hill seems to loose all momentum, needs rapid changing down of gears.... any ideas greatfully received!

Lack of the Go Juice


Suggest you change the fuel filter, if you have not already done so !!!. A well maintained Turbo Fourtrak will be capable of cruising all day at the legal limit, and will do more if asked!!, but their again she was not built as a motorway cruiser. (just keep an eye on the water temp gauge though!!)

Edward (ews)

Edward (ews) '92 Fourtrak 2.8 TDX

the cough indicates

the cough indicates something happening suddenly rather than a gradual blockage og filters... could be a lump of crud movingto partially block fuel or air flow... replace filters and check for obstructed pipes.
however its also possible for the cambelt to have jumped a tooth... either cos its too slack.. or a foreign body has been picked up and carried round between the toothed belt and a cog.
its a case of checking the timing marks on the crank, cam and injection pump, if they are out refit the belt and hope.

Its a good idea to replace

Its a good idea to replace the filters if you haven't done so in a while, but the suddenness doesn't point to that. The no smoke is a good sign,it could be a tooth slipped as the other poster said.

I have got my Non-Turbo F70 up to the ungodly speed of 85 when over taking something on the motorway once! I was suitably scared never to try that again Wink

I cruse along at 60mph.

yeah, check your filters.

yeah, check your filters. fuel and air... if all is ok and it is not blowing black smoke there is a good chance the head is damaged... by black smoke I mean it eliminates the injectors and pump usually if they are missbehaving it will blow alot of black smoke... Mine ran on it's own oil for about 20 seconds.. all seemed ok after except it was down just a little in power.. I pulled the head off and found head gasket was damaged head was cracked and a piston was slightly damaged as well as 2 injectors damaged... just put it all back together yesterday with new rings and bearings and a new head.. I now have my power back...

Thanks, will try filters at

Thanks, will try filters at the weekend and let you know!

1994 F73 Independent - red and rusty!

No smoke shows too little

No smoke shows too little fuel is reaching the engine, this shows in the lack of performance, a fuel filter is the first and cheapest option.

Check for any constriction of the fuel feed pipe, if it is sucked flat it will deliver less fuel to the filter and engine.

It was the fuel filter!

Just changed the fuel filter, had some interesting gunge at the bottom. New filter fitter and now runs well and can climb hills again without many gear changes. Many thanks for advice!

1994 F73 Independent - red and rusty!