I have a Johnson V4 90HP (mid 1980's)on the back of my boat.... I
haven't used it for a while so, as most boat engines, its not performing
like it used to when left un-used for a while....
I want to sell the boat because I just bought a house and I don't really
get enough use out of the thing....
Although I don't to sell a dud so I took it for a drive yestertday.....

It took a little while to start.... not to bad though... was turning over
but just sounded like the petrol wasn't getting through properly or
something... when it was running it ran fine.. (thats with the hose
connected)

Then we took it out into the water..... idling was ok.... driving at about
4knotts was ok.... but after about 5-10 minutes I went to accelerate and
the buzzer went off.... I backed off a bit and it stoped.... tried it
about 3 times, then it was ok....
(The water pump seems to be working fine judging from the water coming out
of it)
Problem was though, I pushed the throttle all the way to the max....
normally the boat would take off really quick.. but instead it barly
moved.... I was getting about 6-7 knots out of it..... I left it in that
position and it slowly increased.... took a few minutes to reach about
18knots..... then it was performing fine.... but whenever I slowed down,
then accelerated again, I had the same slow response.....
Can anyone suggest what could cause this?? Could be a few things I'm sure..
like the fuel.. I need to put some fresh stuff in there..... but is there
anything else???
I believe the engine is in good condition for its age.. its only ever had
minor inexpensive things wrong with it, but I don't want any potentcial
buyers to be turned off by something like this slow response....
I've sprayed WD40 around all the moving parts... (haven't been able to test
it since doing that though) but I don't know if its more likly to be
something internally wrong..... I'm going to put some new spark plugs in as
well... can they cause slow performance???
Any help woudl be most appreciated...
Thanks!