Need Help Tunning Up OMC 3.0L

[playyas4u]

I have a 1992 OMC 3.0L and would like to do a tune up on it. I am not sure what type of spark plugs are suppose to be in there and the gap setting. I do not trust the plugs that are currently in there and would like to know what is suppose to be in there. I will also be replacing the distributor cap, rotor, wires, oil, and oil filter. Are there any other items I should replace for a full tune up? Also what type of oil & oil filter and how much oil do I need? I know I need a manual and will be ordering one soon, but any help will be appreciated. Thanks.

 

[Lodgepole]

Re: Need Help Tunning Up OMC 3.0L

Just did my 3.0 last OCT. Plugs are Champ RS12YC. As I remember, gap is .040. My Boat is in OK. and I am in CO. as is my manual. Oil reccomended is 30 wt. just get a good oil like Valvoline and be sure not to use non-detergent cheap stuf. Mine took 5 quarts with filter. Sorry I can't give you the filter # from here. Might also want to change the fuel filter/water seperator if it has not been changer lately. There is also a fuel filter where the fuel line goes into the Holly carb that you could clean. Believe it or not, I found a new vintage trim gauge on line (perfect match). They had 23 of them. Your exhaust flapper might be another thing to check. Mine burned/rotted off and got hung where the exhaust goes into the drive. Caused back pressure cut out at about 3000 rpm and overheating. Also, don't forget your impeller and thermostat.

 

[playyas4u]

Re: Need Help Tunning Up OMC 3.0L

Thanks for the info. I need to get me a good manual for my boat. Which one do you recommend? The parts that I need do I just go to the automotive store and pick up? Where is the exhaust flapper and do the pipe coming from the manifold out to the outdrive suppose to have holes in it? When I put the muffs on the other day I noticed water pouring form that pipe. Also the vintage trim what is it and where can I get it if I need it? Thanks.