9.8 Tohatsu won't idle good without choke

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63Monark
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9.8 Tohatsu won't idle good without choke

Post by 63Monark » 08 Aug 2016, 13:39

I finally got around to cleaning my carb which i suspected was the issue and a few youtube how to videos later its finally running again. She wont idle good though without the choke all the way out at half choke it will do ok and no choke it spits and sputters could i have done something wrong with the jets or maybe accidently changed mixture screws while handling it any help is appreciated.
1963 Monark 14Ft V-Hull

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63Monark
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Location: Arkansas

Re: 9.8 Tohatsu won't idle good without choke

Post by 63Monark » 11 Aug 2016, 14:46

Anybody?

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DaleH
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9.8 Tohatsu won't idle good without choke

Post by DaleH » 11 Aug 2016, 16:41

Adding choke makes it run rich, so you're probably too lean.
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wmk0002
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9.8 Tohatsu won't idle good without choke

Post by wmk0002 » 11 Aug 2016, 16:48

So having to have the choke all the way out is richening it up which means at no choke it is way too lean. This could be from slow speed needle adjustment being too lean, or clogged idle passages or a combo of both. It could also mean you have an air leak at the gasket for the carb/manifold connection. It could also mean you have a sticking needle valve or faulty fuel pump and your carb bowl is not filling up, but if this were the case it would not run well at high speed which you didn't mention was a problem.

Have you tried messing with the slow speed needle adjustment any? As long as you note its current position you can toy with it and return it back no problem. I'd start it at 1 & 1/2 turns out from lightly seated and then back it off 1/8 turn at a time with 10 second pauses between adjustments. If you get to 3 turns out and no noticeable change then I would revisit the carb. Sometimes after a cleaning debris can still be washed in from the fuel tank or fuel lines and clog the slow speed passages even if you cleaned the carb perfect. The only way to tell is to pull it apart again though.
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63Monark
Posts: 29
Joined: 11 Mar 2016, 16:16
Location: Arkansas

Re: 9.8 Tohatsu won't idle good without choke

Post by 63Monark » 11 Aug 2016, 23:29

At this point I haven't messed with screws ive been wondering if I put jets back in wrong or tightened them too much when I went outside today with new plugs and a new fuel filter I discovered my fuel line now has a air leak in it and the primer won't build up pressure hopefully ill get it straightened out this weekend thanks everybody

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Fadec
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9.8 Tohatsu won't idle good without choke

Post by Fadec » 12 Aug 2016, 10:13

Sounds like a clogged jet. I had the exact problem with my Merc. 9.9 last summer. The debris in the needle was so bad I to use a small piece of wire to clear it. Carb cleaner just wouldn't cut it.

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