01 Suzuki DT140 engine underpowered--HELP

[my3sons]

First, I am very new to the boating world and my marine engine knowledge is very limited. I will order a service manual soon to educate myself but I have an immediate problem with my DT140 engine. The engine power appears to be severely reduced particularly during take-off. My more experience fishing friends all have echoed the same sentiment. During the last cold fishing trip, we noticed the following on my 196 Fishmaster center console boat out of the hole. The engine is DT140, 2-cycle EFI, prop pitch is 19 deg and WOT appears to max out at less than 5000 RPM. The spec says WOT should be around 5700 rpm. On several occassions the engine cut-off due to temp overheat. Again, out of the hole the cooling water (peeing) did NOT have constant volume and pressure and white smokes and eng straining noise follow. There appears water bubbles developing around the joint area between the top and bottom unit. Again, WOT max out at less than 5000 rpm. Previously, I could it to max around 6k at WOT. I don't believe the boat can now achieve speed greater than 30 mph. I am very concern with already damaging the eng. I am also very skeptics of dealers servicing the engine and would rather do the work myself if equipped with the knowledge which I hope will be provided in the svc manual and forums like this. Any help/suggestion is greatly appreciated.

my3sons
DFW :^:^:^

 

[JUSTINTIME]

Re: 01 Suzuki DT140 engine underpowered--HELP

compression check
spark check
check tps sensor should be 250ohms +/- 25 ohms
sounds like u need a water pump, or check the cooling passage ways
check spark plugs and post pics

 

[deejaycee_2000]

Re: 01 Suzuki DT140 engine underpowered--HELP

welcome to iboats ...... check your thermostat, sensors, and time for a impellar change .... make sure the motor is getting enough oil ....

 

[my3sons]

Re: 01 Suzuki DT140 engine underpowered--HELP

thank you gents.

I may have found the real culprit. I found that my prop spacer is missing which leaves about 1/2 inch gap between the prop and the lock nut with cotter pin. There maybe other problems that could contribute to this engine underpower but in my opinion this gap (free play) could cause a major power (thrust) loss during take-off. The prop kit should arrive soon. Anyone have any suggestions/ideas?

thanks,
my3sons

 

[rwash91]

Re: 01 Suzuki DT140 engine underpowered--HELP

I wouldn't think that a loose prop would have anything to do with your water intake and pressure. I sure wouldn't run it untill I had it fiquered out for sure.

 

[DJ]

Re: 01 Suzuki DT140 engine underpowered--HELP

I may have found the real culprit. I found that my prop spacer is missing which leaves about 1/2 inch gap between the prop and the lock nut with cotter pin. There maybe other problems that could contribute to this engine underpower but in my opinion this gap (free play) could cause a major power (thrust) loss during take-off. The prop kit should arrive soon. Anyone have any suggestions/ideas?

That's not it. If your prop were slipping, your RPM would be greater, not less.

Number one priority is a compression check to see if you cooked the engine. If that's OK, you need to service your cooling system.