high idle on Suzuki 140

svilla

Seaman
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Jul 29, 2003
Messages
64
I have a 1987 Suzuki DT140. I just recently pulled and cleaned the carbs and replaced the fuel pump and all fuel lines. When I start the engine idle picks up then goes back to normal, but after 3 min it idles super high (like around 3000RPMs). This motor has me stumped.<br /><br /> Anyone have a clue on what to check next?
 

deejaycee_2000

Captain
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Mar 28, 2006
Messages
3,447
Re: high idle on Suzuki 140

Have you tried adjusting the idle speed adjuster on the motor? You probably did, but I had to ask .... you cleaned your carbs right? ... there is your problem, you gonna have to start adjusting those carbs you must have somehow changed the adjustments while cleaning them ....
 

svilla

Seaman
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Jul 29, 2003
Messages
64
Re: high idle on Suzuki 140

yeah I check the idle adjust on the side of the motor. And the only adjustment on the carbs I know of is the pilot screw, and that is 1 1/2 turns from soft stop. What othere adjustment can I make to the carbs? This is really frustrating. <br /><br /> The motor starts normal, idle's down normal, then the RPM's go really high, like arount 3000RPM. I can flip the choke on and get control of the RMP, but when I open the chock the motor will go back to 3000RPM. If I leave the choke on the motor dies.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: high idle on Suzuki 140

check the ign timing while its runnig fast, if its 11* BTDC or more check the throttle valve switch/sender if it has one.<br /> takes 3 things to increase RPM. advanced ign timing,more fuel and more air. find out which ones its getting.
 

svilla

Seaman
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Jul 29, 2003
Messages
64
Re: high idle on Suzuki 140

yeah the #4 carb has a Throttle valve switch, and I had the wires off it. So that is suspect. And I just relized that #2 and #3 carbs are switched around, #3 has a 162.5 main jet and #2 has a 155 main jet. So I will switch those around, I just dont know why that would make much differnce. <br /><br /> Also the Suzuki manual say's the hose off the fuel pump goes in a certine order as well. Is there a high and low pressure side to the fuel pump? and would this make alot of differnce in RPM? <br /><br />Could the throttle valve switch add that much timing to make it run 3000 RPM?
 

svilla

Seaman
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Jul 29, 2003
Messages
64
Re: high idle on Suzuki 140

worked on the motor again today. This time I got the motor started every thing seemed ok. Then the rpm jumped up to 5500 and she died. I had to pump the fuel ball to fill the fuel bowls before I could get her to start. Will running the fuel bowls out of gas cause the rpm to rev to 5500? And I just replaced the fuel pump last night. It might be posible that I got a bad pump, but I dont know what is causing the high RPM's.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: high idle on Suzuki 140

its getting air,fuel and ign timing advance, cant get RPM without it.<br /> the ECU on that motor controls the ign timing. thats why you have to check it.<br /> other than that correct linkage adjustments and correct TVS voltages are critical.
 

svilla

Seaman
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Jul 29, 2003
Messages
64
Re: high idle on Suzuki 140

how do I check the ECU, and what is TVS
 

svilla

Seaman
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Jul 29, 2003
Messages
64
Re: high idle on Suzuki 140

Ok I have the out of control RPM trouble-shot to the TVS (throttle valve sensor) I re-calabrated it per the book. Now I have a fuel problem, I cant keep the bowls filled.
 

svilla

Seaman
Joined
Jul 29, 2003
Messages
64
Re: high idle on Suzuki 140

Ok TVS is fixed, and I found my fuel problem. I took the fuel tank apart and found a split fuel pick up tube. I replaced that and she runs fine on muff's. I will put her in the water tomarrow and adjust my carbs, keep your fingers crossed.
 

svilla

Seaman
Joined
Jul 29, 2003
Messages
64
Re: high idle on Suzuki 140

well took her to the boat launch, on my lunch break. She ran like a champ, I will take her out tomarrow.
 

jaymiah

Recruit
Joined
May 15, 2011
Messages
1
Re: high idle on Suzuki 140

Ok I have the out of control RPM trouble-shot to the TVS (throttle valve sensor) I re-calabrated it per the book. Now I have a fuel problem, I cant keep the bowls filled.

hey, i am having the same high idle problem and i cant figure it out.. how do i re-calabrate the TVS. I am thinking thats my problem also
 

mike8353

Recruit
Joined
Feb 10, 2012
Messages
3
Re: high idle on Suzuki 140

hey, Im having pretty much the same issue, had the carbs off and when I put them back on the idle rpm goes straight up to around 4000 and dosnt come back down.
If I put it straight into gear before the revs get too high it runs really well and putts along at under 1000 rpm nicely, but as soon as I put it back to idle the revs run away again.
I had the tvs hooked up at first but then disconnected it completely and it made no difference whatsoever.
Its frustrating because I took the carbs off for a different issue and it was idling fine before that.
How do I tell if the tvs is faulty?
Any advice would be great.
Thanks
 
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