Optimax 200 1999 low rpm

Joined
Jun 4, 2011
Messages
2
Hi

I have a Merc 200 Optimax 1999 on a 18ft fishingboat

It starts up fine and runs great but if i run it on idle or low/middle rpm and give it full trottle it accelerate real hard up to around 4500 rpm and then it drops off and slowly rev up to 4800-4900 and there it stops , i have tried smaller props whitout any changes.

Last summer i have a Merc 175 Optimax and it revs 5500 rpm and the boat was doing around 48 kn. but this year whit the 200 it?s only do 45 kn at 4800-4900 rpm , how fun is that ? :confused:

Any ideas anyone ?

The fuel , fuelfilter and sparkpluggs are new , new impeller and termostat?s.

Someone told me if one of the temp.sensors does?nt work or if the blockwaterpressure is to low the rpm might drop 25% ???
 
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