Merc 120 SportJet wont start

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Cadet
Joined
Jul 6, 2007
Messages
7
I just bought a Sea Rayder 96 with about 170 hours on it. It has a Merc SportJet 120. It is in the midwest and was last used 2 years ago. The previous owner said it was winterized the 2 years tey owned it and then 2 years ago they took it out in spring and it wouldnt start. Turn key and abslutly nothing , no sound. They said a marina told them it was a bad bad battery, they put new one in and nothing happend.

They told them it must be the starter motor so they said forget it and put it in teir garage where it sat for 2 years. The gear on the starter was in the "start" position so the flywheel wouldnt turn. I put a new battery and starter in and when I turn the key and flip the toggle switch to start it, I hear one "click" back near the starter or solenoid or? but nothing else no click click or anything just "click"

When I turn the key the gauges (fule goes up to 3/4 tank) all go up for about 3 seconds, then they go back down even though I didnt turn the key back to off. The blowers dont turn on either but the lights and the bildge pump do go on when you flip the switch. Maybe I am doing something stupid but any ideas would help. I also took the plugs out and they are kind of brown, dirty and a bit oily. I was going to turn the motor over to blow the cylinders out but it wont do anything but that one click. Once I replaced starter and the gear was disengaged and no plugs I can turn the flywheel by hand so it is not siezed.

I did note in the manual that it said the butterflys on the 2 carbs need to be in total sync and closed all the way or the "turn key start will be disabled" I didnt try to align them or mke sure they are properly in sync but could that be disabling the engine from starting? Thanks in advance for any ideas
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Merc 120 SportJet wont start

90% of starter problems are bad connections. remove and clean both ends of the battery cables, so that they are shiney, also the cable from the solenoid to starter. check for nicks in the cables. and make sure the connectors are on the wire good. the cable tend to corrode from the inside out, if nicked, corroded wires, and connections, heat up and cause resistance to the follow of electricity, thus the starter doesn't get enough. you can also take jumper cable pos battery post to large post on starter. with a good connection, the engine should spin. then if the starter is good clean everything and retest. then trouble shoot solenoid. starters can be rebuit at a starter/alternator shop, much cheaper than a new one.

also have the battery load tested at the auto parts store, free, i've had new batteries go bad
 

fogarmj

Recruit
Joined
Jul 25, 2007
Messages
2
Re: Merc 120 SportJet wont start

I just bought that same boat with similar issues. i took it to a marine mechanic after i could not get it started. i was able to turn mine over with the starter after charging the battery. the mechanic told me that the carbs needed rebuilding. if i were you and you are mechanically inclined, i would start with the battery and starter and get it turning over, then go with plugs and wires and move onto fuel system and see what you get. just be sure you have good gas and clean fuel filter before you start.
 

fogarmj

Recruit
Joined
Jul 25, 2007
Messages
2
Re: Merc 120 SportJet wont start

I just bought that same boat with similar issues. i took it to a marine mechanic after i could not get it started. i was able to turn mine over with the starter after charging the battery. the mechanic told me that the carbs needed rebuilding. if i were you and you are mechanically inclined, i would start with the battery and starter and get it turning over, then go with plugs and wires and move onto fuel system and see what you get. just be sure you have good gas and clean fuel filter before you start.
 
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