Good morning everyone, I have a Mariner 90hp outboard with carburettors from 2000 (if I'm not mistaken the same as the 100hp Yamaha), which in practice no longer takes all the revs it should take... last season with the same set up I got 35 knots ( at around 5000 rpm) with two people on board while now 25 (at around 4000 rpm) with only one person on board!
The engine has new engine oil and crankcase oil, new impeller, the hull is clean (I keep it dry and I only take it out when I go out), carburators have been cleaned a couple of weeks ago (thinking that this was the problem), various petrol filters all new and new spark plugs.. the coils were even replaced thinking in a faulty coil..! None of this had any effect...
the boat obviously did not take on any water and the propeller was not changed)
Does anyone have any ideas on what it could be?
PS: aside from the fact that it can't go above 4000/4100 rpm, otherwise the engine is perfectly smooth, it doesn't mumble, it doesn't shut off, it starts right away and has no sudden drops in power!
thanks to anyone who can help me!
The engine has new engine oil and crankcase oil, new impeller, the hull is clean (I keep it dry and I only take it out when I go out), carburators have been cleaned a couple of weeks ago (thinking that this was the problem), various petrol filters all new and new spark plugs.. the coils were even replaced thinking in a faulty coil..! None of this had any effect...
the boat obviously did not take on any water and the propeller was not changed)
Does anyone have any ideas on what it could be?
PS: aside from the fact that it can't go above 4000/4100 rpm, otherwise the engine is perfectly smooth, it doesn't mumble, it doesn't shut off, it starts right away and has no sudden drops in power!
thanks to anyone who can help me!
