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Suzuki DF25 V-Twin Four Stroke Outboard Motor Engine light comes on at full throttle.

Whitebuzzbait

New member
My son has a 2007 Suzuki DF25 V-Twin Four Stroke Outboard Motor. The check engine light comes on when you run the motor at full throttle for about a mile. It is then at reduced speed. You can run it at reduced throttle all day long with no problem. When this light comes on you can restart it to get it to run normally. It has new plugs, new oil and oil filter. The water pump was replaced and pumping fine. The oil pressure switch has been replaced. It has about 30 psi oil pressure at idle but I do not know what is normal. We tried a different prop as well. I think about all that is left is the temperature sensor or the thermostat. I read in his service manual ¨do not overfill the engine oil or damage to the engine could occur.¨ I found that my son had double the amount of required engine oil. I drained the oil and did an oil and filter change to correct that problem. I do not know how long he had been running it like that or what damage could occur. All parts were replaced with Suzuki OEM parts. Does any one know what is wrong.
 
I have been having same exact experience and do not have the answer. When I got the motor, it was overfilled with oil and I didn't deal realize it. It ran fine. When I finally changed the oil and put the correct amount, it started to have same symptoms you mentioned. Brought it to a shop and they couldn't duplicate the problem... cost me $100 just for that. Any new info you may have learned?

Scott N


My son has a 2007 Suzuki DF25 V-Twin Four Stroke Outboard Motor. The check engine light comes on when you run the motor at full throttle for about a mile. It is then at reduced speed. You can run it at reduced throttle all day long with no problem. When this light comes on you can restart it to get it to run normally. It has new plugs, new oil and oil filter. The water pump was replaced and pumping fine. The oil pressure switch has been replaced. It has about 30 psi oil pressure at idle but I do not know what is normal. We tried a different prop as well. I think about all that is left is the temperature sensor or the thermostat. I read in his service manual ¨do not overfill the engine oil or damage to the engine could occur.¨ I found that my son had double the amount of required engine oil. I drained the oil and did an oil and filter change to correct that problem. I do not know how long he had been running it like that or what damage could occur. All parts were replaced with Suzuki OEM parts. Does any one know what is wrong.
 
I have been having same exact experience and do not have the answer. When I got the motor, it was overfilled with oil and I didn't deal realize it. It ran fine. When I finally changed the oil and put the correct amount, it started to have same symptoms you mentioned. Brought it to a shop and they couldn't duplicate the problem... cost me $100 just for that. Any new info you may have learned?

Scott N
We have not figured it out. The engine runs great at less than full throttle and we can run it full throttle but not for very long. Usually in some of the smaller lakes we fish this is no problem since we are all the way across the lake before it goes into limp mode. I think my son has chosen to ignore the problem rather than pay a service as you did.
 
Well I want to sell mine and would like to get it working 100%. I have a guy that will look at it for me. I will let you know what he finds.


We have not figured it out. The engine runs great at less than full throttle and we can run it full throttle but not for very long. Usually in some of the smaller lakes we fish this is no problem since we are all the way across the lake before it goes into limp mode. I think my son has chosen to ignore the problem rather than pay a service as you did.
 
I had the thermostat removed and it is running like a charm. The problem went away. I didn't put a new thermostat since there wasn't one immediately available, but it should be fine without.
 
Sorry not sure how to start a post. I'm trying to find what year my outboard is it's a suzuki dt4 00402 501067 thanks. Dan
 
I think that's a problem with over rev.
I'm almost certain that's what it is on my 06 DF25, Which does the same thing.
The problem is I can't find out how to adjust the throttle limiter.
 
I have a 2017 DF300ap, 900 hours, with two four-inch lcd gauges, one set for fuel and the other as a tach. During a trip yesterday the screen on the fuel gauge reverted to showing the Suzuki "S" emblem and the system started beeping. There were a few (0 - 3) short beeps, followed by a string of ten beeps. There were no error displays or warnings. The motor worked fine after the beeping started, with no reduction in rpm's. I recently had all fluids, the water pump, and the trim motor replaced. Any help would be greatly appreciated!

Dr Car Polisher
 
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