1975 402 40 hp mercury

[grizzreaper]

hello hope someone can help me with two things

i started my motor and a cant seem to get it to stay running. it smokes really bad and chugs sputters and jumps around. i put fresh gas in i was told 50:1 oil mix. i did remove the fly wheel and stator but i did mark it before removing. i think i put everyting back they it was but i might been off a hair or two. i dont have a manual for it. i was wondering what steps now do i take to set the timing back up on this.

2nd thing is i did a really stupid thing and left the gas hooked up to my 9.9 and did not run the gas out. so the gas has been sitting the carbs for three months now. what steps do i take now to fix this problem before it becomes a headache thnx in advance for all help.

 

[oldgradywhite]

Re: 1975 402 40 hp mercury

First things first I would take the carb apart and let it sat in yamaha carb dip for at least a day. Then get all new carb parts and rebuild it. Gone are the day when all you needed was a can of carb cleaner to clean carbs. This e85 is the worst thing your carbs. Being a 1975 I don't know if you have points or not if you do I would replace them too. If you had the flywheel off you would have seen them.

 

[daveswaves]

Re: 1975 402 40 hp mercury

hello hope someone can help me with two things

i started my motor and a cant seem to get it to stay running. it smokes really bad and chugs sputters and jumps around. i put fresh gas in i was told 50:1 oil mix. i did remove the fly wheel and stator but i did mark it before removing. i think i put everyting back they it was but i might been off a hair or two. i dont have a manual for it. i was wondering what steps now do i take to set the timing back up on this.
.

First things, there are no points. Second you can,t be off a hair or two, you are either right on or way off. To check, remove the number one plug, insert a long pencil or other non scratching tool, plastic, wood. The wooden spoon from your wifes kitchen drawer works well. Rotate the flywheel clockwise until the spoon stops pushing out and starts to retreat. Check the timing pointer and see if it points to TDC or 0 degrees on the timing sticker. If it does your flywheel is on correctly. The timing may or may not be "off", but the flywheel is on correctly.

This sounds like a new motor to you, do you know its history, have you ever heard it run smoothly??

 

[grizzreaper]

Re: 1975 402 40 hp mercury

thanks and it is a new motor to me and i never heard it run . i just replaced the choke sel, rectifier, and starter sel. i went to replace the stator but the one i got was the wrong one. so i put the old one back in. i just picked up another 1975 402 40 hp thunderbolt but its a short shaft. now i am strupmed on what to do .