Ok i have finally identified the problems on my mercury 650!

Mercury 650 65hp 2stroke 4 cylinder<br /><br />Some guy answered me on the forum that it is having a sneezing problem where the engine like coughs and jolts every few seconds.<br />Also the boat seems to be coughing out heaps of smoke! When i mean heaps i mean the driveway is fogged up with it. <br /><br />Im no mechanic but I want to have a go at fixing it before i take anything to mechanic<br /><br />What do you think i should do exactly to this motor? But not rebuilding the carbs <br /><br />Thnaks

Re: Ok i have finally identified the problems on my mercury 650!

as in everything i should do to it to get it back into ship shape.. And can someone estimate how much it will cost excluding labour (just parts and ****)

Re: Ok i have finally identified the problems on my mercury 650!

Sorry to say this but you need to overhaul carbs, especially replace needle and seats, but on a softer note your sneezing can be fixed (maybe) by turning the idle speed adjustments on each carb out 1/4 to 1/2 turn. To really get that motor in tip top you need ths carbs cleaned, new needle and seats, replace fuel pump diaphrams, and new plugs points and condensor. You will need a manual to be able to do this so estimate about $100 to $120 (US). I also have a 67 65hp merc and they are really easy to work on, just spend time reading the manual and when you need extra help post back as there are some very knowldegable people on this site.

Re: Ok i have finally identified the problems on my mercury 650!

What manual should i get that covers the thunderbolt ignition mercury 650's (i don't know the exact year of mine and can't find out coz no serial)

Re: Ok i have finally identified the problems on my mercury 650!

Mine is for all mercury from 1966 to 1974. Its a mercury factory manual and has pretty good instructions, have also looked at the Clymer manual and it is ok.

Re: Ok i have finally identified the problems on my mercury 650!

you also might want to add a water pressure gauge in your dash 0-15 psi works good. idle pessure is about 3 psi and wot is about 8 psi.