suzuki dt-140 idles ok full throtle problem

sidla · May 27, 2007

1988 larson 17 feet with suzuki dt-140.
idles ok throtling to 2000 rpms ok,when giving full throtle nothing changes or even rpms drops under load,if engine not under load(raised) throtles just fine.
some advices?
where i csn find repair manual for that engine?
thank you

alphamax · May 27, 2007

Re: suzuki dt-140 idles ok full throtle problem

Could have a problem with stator or switchbox not working well, more times stator have two function circuit one for low rpms and one for high rpms, sintoms of your sound like a high rpms circuit not working...

sidla · May 27, 2007

Re: suzuki dt-140 idles ok full throtle problem

find out if engine fully under water the problem exists(in lake) if in home with small ammount of water throtles just fine... head or head gasket problem???
thanks

alphamax · May 28, 2007

Re: suzuki dt-140 idles ok full throtle problem

When you say in lake you mean with the engin in forward gear or neutral?
It's only a difference of level water ???

sidla · May 28, 2007

Re: suzuki dt-140 idles ok full throtle problem

lets start from begining:
at home with water lane connected engine works normal,water light some times blinking so i think engine lines not fully filled with water...engine works on idle and full trhrotle.
in lake:lowering motor water light never goes on engine lines fully filled with wother engine rough working at idle some times shuting of looks like cylinder(s) not works,full throtle max 2000 rpms.
the problem starts when the engine fully under water....
i think cylinder head or gasket problems but need some advices from professionals or guys who get same problem,i am car mechanic but never work on 2 cycle outboard,or another boats thats my first on+ still do not have repasir manual
thank you

sidla · May 28, 2007

Re: suzuki dt-140 idles ok full throtle problem

p.s compression in all cylinders 115-118.

sidla · May 28, 2007

Re: suzuki dt-140 idles ok full throtle problem

change gasket check head everything ok,still no luck...
any help? missfires sometimes...

grid · May 28, 2007

Re: suzuki dt-140 idles ok full throtle problem

You're shooting a shotgun at this and you need to take a deep breath and start again. You say the water light comes on. This means the water flow sensor in the head is stuck--or telling the truth that the water pump is weak. When that light comes on, revs reduce to save the engine and alert the operator of a problem.

You haven't stated if this is EFI or carbureted. If it's EFI, you'll need to follow a FACTORY manual to diagnose the problem. If it's carbureted, have somebody drive the boat while you put your hand over one carb at a time. If the engine picks up RPM when you do that, your problem is blocked main jets. For that the carbs have to be removed and (best) sonic-cleaned.

You might also check the TPS on the port side of #3 carb. That advances the timing when accelerating. Disconnect one of the non-ground wires at a time to see if there's a change in accelleration.

sidla · May 28, 2007

Re: suzuki dt-140 idles ok full throtle problem

the light sometime blinking when connected to water line at home,just some times,in lake no light and..... no power :/ 2000 rpms and thats it...
man man mess with it all hollidays no luck,but going make it,must order manual and....
thanks for answer

JUSTINTIME · May 28, 2007

Re: suzuki dt-140 idles ok full throtle problem

what year suzi?
so we know carb or efi

sidla · May 29, 2007

Re: suzuki dt-140 idles ok full throtle problem

sorry: 1988 17 larson,with 1988 suzuki dt-140,carbs on it cdi,oil injected,
the engine looks like rebuilt not long time ago,runs erraticaly no power uder load sometimes missfires,small ammount of oil comming out from exhoust, what is the best repair manual i can get on internet?
thank you

deejaycee_2000 · May 29, 2007

Re: suzuki dt-140 idles ok full throtle problem

the one on www.brownspoint.com ......

sidla · Jun 17, 2007

Re: suzuki dt-140 idles ok full throtle problem

still no luck,think have crack inside cylinder head or power block,yesterday after trying in lake,get stucked water temperature sensor,atfter removal got some exoust smoke from sensor hole... somebody has ideas where i can check cylinder head and power block for cracks in chicagoland???
thank you

corrjas · Jul 14, 2008

Re: suzuki dt-140 idles ok full throtle problem

You Might Try Adjusting Your Throttle Control Sensor. That Is The Trouble I Had. The Correct Voltage Should Be Between 0.45 Volts And 0.55 Volts At Closed Throttle

James R · Jul 14, 2008

Re: suzuki dt-140 idles ok full throtle problem

Could be more than one issue but the first one could be dirty carbs so the motor is running on a weak mixture, When were the carbs last cleaned. If you dont know then that is the first thing to address. Always use Stabil or a similar additive to help those carbs stay clean.
Next,could be a weak fuel pump.
Next, a strong water telltale is no real indication that the motor is getting cooled. Run the motor and put your hand on the block and the head and the exhaust cover and see if they are at a reasonable temp', You will know if there is too much heat. The weak mixture can cause overheating.
Next. You have a self oiling system and I might add, one of the best out there. However even this needs to be checked out. The test is in the manual.
In addition pull each oiling tube from its brass tube at the inlet manifold and make sure that oil is oozing out when the motor is running. Use a jug of 50/1 mix to facilitate all the oiling tests. The motor will then be lubed even with the oiling system disconnected.
Get a Seloc manual from Ebay
I rebuild these Suzukis and Run a DT140 on my BR.

seaox21 · May 12, 2011

Re: suzuki dt-140 idles ok full throtle problem

This is an older posting but I am having the same issues. The boat runs at home with the hose connected but when I trailer it to the ramp it starts and runs rough, then stalls while increasing RPM's or shifting into gear. Very frustrated at this point.:facepalm:

CobraCommander · Aug 24, 2011

Re: suzuki dt-140 idles ok full throtle problem

go out with a partner. have him open throttle and when engine begins to stall, pump the primer bulb for about 10-15 seconds and see if engine revs up. If it does you either have a bad bulb or fuel pumps are weak. Throttle control sensor should be checked with a multi meter also. If not these things, you can rebuild carbs and make sure you have clean fuel.

99yam40 · Aug 24, 2011

Re: suzuki dt-140 idles ok full throtle problem

Please start a new thread for your problems as this one is old and started in 2007

seaox21 · Aug 25, 2011

Re: suzuki dt-140 idles ok full throtle problem

I have fixed the problem , hopefully this will help others. I narrowed the problem down to the thermostat was junk and the overheat alarm was not working. The overheating engine would sputter and stall. I replaced the thermostat, overheat alarm and sensor and just to be safe a new water pump. The engine has never run better. Thank for all the advise.

suzuki dt-140 idles ok full throtle problem

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