Flat spot at 2500

[bluematt1]

Dont know if anyone can help have an old 200 merc 93/94 ish has an annoying flat spot at approx 2000-2750rpm anymore its clear any less its clear when was last out it was the most slightest of change of engine speed it was either slightly flat or fine as if turn a switch on or off have had carbs cleaned overhauled new fuel filter plugs new stator and flywheel had a look in tank looks fine and is venting ok its really bugging me if you get my drift last year plugs seeemed to fix it for a few hours thats why i went for stator heard its a sign of stator failing just had a look at connections on wires going onto some boxes from coils are these switch boxes?? going to clean up and try problem is only there under load so have to put in water to know if cured oh and ive tried giving choke also when it does it no difference basicly if driven flat out its fine and keep over 3000 but if going through harbour its a bit of a pain anyone have any ideas looked on various problem sites and it seems to be quite common oh one other thing every now and then rev counter doesnt work may be related may not this has only happened at home though never whilst out

[Burty]

sounds like the carbs aren't set up correctly and its bogging down when switching to main jets

[bluematt1]

Originally Posted by Burty

sounds like the carbs aren't set up correctly and its bogging down when switching to main jets

Noticed on switch box some of the threads are rusty where ring terminals are under the little gaiters
When I was last out it felt more electrical than fuel though

[bluematt1]

Originally Posted by bluematt1

Noticed on switch box some of the threads are rusty where ring terminals are under the little gaiters
When I was last out it felt more electrical than fuel though

come on someone must have a few clues

[Techteam]

Have the baffle plates in the carbs been re riveted with pop rivets by any chance?

[bluematt1]

where /how would you see are you talking about butterflies ?? where are bafel plates

[Techteam]

Some of the carbs were fitted with a baffle plate in the float chamber. Its blind riveted through the venturi. Sometimes the plate works loose and is re riveted with a pop rivet. Look down the venturi and look for a silver dot in front of the emulsion tube at the bottom, if it sticks up like a pop rivet not just a dot then that could be the problem.

[bluematt1]

have had carbs looked at by russell power boats he cleaned and set up carbs would you think he may of noticed ??
I had air filter off the other day didnt notice any pot rivots down venturi