My suzuki 140 runs good on the muffs but not in the water?

[Jessejames]

Anyone know what could be wrong with my motor? It runs and idles fine in the driveway . Put it in the water and it doesn't run good at all. Hard to keep running and gutless wont rev up. I checked compression and had good compression on all 4 cylinders its a 93 suzuki 140 oil injected 2 stroke.

[WEDOCQ]

Just curious, when you run it in the driveway, is the cover off?
-Shawn

[artdf175]

So what is the history of the engine?
Is this first attempt to run it?

Spark plugs? New - used?
Fuel? Old? new?
Fuel filters?
Art

[Jessejames]

I put fresh premium in a small 6 gallon can and connected that to the fuel line. It fired right up. I got the boat cheap because they had this problem. It ran the same in the driveway with or without the cover off. I didnt try replacing the spark plugs cause they all looked good. They said before they replaced the brain box and it ran good for a few years then it did this again. Idk awhole lot about outboards but ive learned alot in the last year!

[Jessejames]

When i got fresh fuel hooked to it. I manually choked it and i fired right up. I shut it off and barely bump the key and it fires right back up and idles . When i was in the water with it the boat kinda struggled to get running and when in gear it would barely rev up above idle even at full throttle. We manually half choked it while in the water to help it stay running to get bback to the dock

[Jessejames]

Also the guy i got it from is a small engines mechanic and he said they tried cleaning the carbs with no different results! Could it be a bad fuel pump?

[artdf175]

Can i assume it is a 2 stroke DT model
2 stories are not my expertise
I don't know if your model mixes oil as it runs or needs a premixed source
However make the assumption the fuel is not the problem then
Spark plugs would be first on the list to replace
Brand new fuel would be #2-- did you open the tank vent so running the engine does not create a vacuum in the tank?
You said the former owner cleaned the carbs
Did he replace the gaskets?
Needle valve reset correctly?
Fuel filters are cheap and should be double checked
Fuel pump? Maybe
If you get ot running in your driveway -- warm it up
The take the hose off the 'out side 'of the pump - put it in a container to catch fuel-- start engine Can you
close off the fuel with finger pressure ?
If so you should check the diaphragm
Anyway some ideas on things to check
Art

[catacom225]

Just a thought but my DF140 runs like crap on premium , It preferes 91 octain

[Solarman]

Jessie, you have a '93, dt-140, this is a 2 stroke.

Might test the throttle position sensor (tps) and the gear counting coil by the manual. Assuming the carbs and fuel pump (check clear discs-check valves- if broken, pump(s) has to be replaced) are good. The position of the gear counting coil next to the flywheel is extremely important, it must count every tooth, or timing is off.

I am guessing this is NOT the fuel injected motor, with carbs.

Do you have guages / tach / suzuki monitor connected? Are any lights flashing?

If the carbs haven't been cleaned properly and reset to the manual specs, there is a reason it won't run well.

If your carb has different size jets between the 4 carbs, and they got mixed up, that would be another reason.

These carbs only run good if they are soaked well and every fuel & air pas-sage are blown-out thoroughly with compressed air. After cleaning, all 4 air mixture screws are set identically at manual specs (my '99s are set at 1.5 turns open, from lightly seated).

Post back with some info, and responses. Good luck.

[Jessejames]

Thanks . It is a carburated motor. Two stroke oil injection. Im going to be bringing it to a shop to have them look at it!

[bladenbullet]

ignition timing possible concern...in the water there is much greater backpressure on the exhaust side of the engine creating a load and changing the fuel burning properties...