please help. my 40hp yamaha isnt burning fuel correctly

[darinsray]

hi, ive just inherited a carolina skiff 16 with a 40 hp yamaha p blend 3 cyl. I replaced the gas and spark plugs, checked oil level's and put ears on it and got it to crank up. it sounded real drowned out and alot of gas. i let it warm up then i attempted to put it into gear and it wouldnt get out of low even when it was in high. the engine kept dieing and i had gas spitting out the center carb before i changed the spark plug, i took it to the lake today and same problem. reverse and forward only go in low gear and it kept dieng, towards the end of the trip it stayed running fairly decent but still i had a gas film on the water behind the boat. ive never adjusted timing on a engine, ive only ever seen it done, the engine looks really clean and taking care of it just sat for years. thanks for your time , darin

[darinsray]

another step

i just went outside and tried to fire it and it wont stayed started at all now. (glad i got out of the lake when i did) only the top cyl seams to be working and the center one i know isnt fireing cause it starts with the plug disconnected. so thats where im at now and i have no clue what i need to replace or do, ive checked the wires going to the cyl spark plug areas and they seam fine, im missing something

[99yam40]

Check compression,
spark with a spark tester,
timing with timing light,
and fuel pressure/vacuum with gauge.

Then if all is well pull and clean the carbs and follow the link and sync procedure in the service manual when reinstalling carbs.
Make sure to clean out tank and fuel lines as anything in them will end up in your cleaned carbs. Sitting for years is tough on a motor

A model # would help identify your motor

[darinsray]

thanks

1990 and i found serial number, need to look when the sun is out for the model #
serial is 6h4s103878 its two stroke auto oil blend.