1998 DT225 RPM issues

wbas1

Petty Officer 2nd Class
Joined
Aug 7, 2020
Messages
127
I was looking for some help on an issue I am having. I have a 1998 DT225 Suzuki EFI and I cannot get the boat past 1000 RPMs under a load. In neutral all is fine. I have looked all over the forums and cannot seem to find a solution. I have changed the following this winter. Plugs, Oil Sensor, water separator & checked the fuel. I am going to change the fuel filter to see if that helps. Any direction would be greatly appreciated.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,086
under load the motor needs more fuel.
make sure the high pressure pump is keeping rail pressure in spec.

I know nothing about your Susuki, but some motors will keep RPM down if there is a failed sensor the ECU needs to be seeing working correctly
 

wbas1

Petty Officer 2nd Class
Joined
Aug 7, 2020
Messages
127
under load the motor needs more fuel.
make sure the high pressure pump is keeping rail pressure in spec.

I know nothing about your Susuki, but some motors will keep RPM down if there is a failed sensor the ECU needs to be seeing working correctly
That will be one of the tests that I will run. I am checking the fuel filter tonight.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,082
When did it start acting up?
Have you checked the compression?
 

wbas1

Petty Officer 2nd Class
Joined
Aug 7, 2020
Messages
127
When did it start acting up?
Have you checked the compression?
It started the end of last year. Had the boat for a couple months then the last trip out it acted like this. we put it in the water yesterday and gave it gas and it only went to 1000k. No backfire no bog nothing. I am checking compression tonight
 

flyingscott

Fleet Admiral
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Apr 8, 2014
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8,095
Compression and spark test must be done. Sounds like you are not running on all six cylinders. Neutral revving means nothing!
 

wbas1

Petty Officer 2nd Class
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Aug 7, 2020
Messages
127
It started the end of last year. Had the boat for a couple months then the last trip out it acted like this. we put it in the water yesterday and gave it gas and it only went to 1000k. No backfire no bog nothing. I am checking compression tonight
Compression is 120PSI on all cylinders.
 

wbas1

Petty Officer 2nd Class
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Aug 7, 2020
Messages
127
I just tested spark and see I have no spark on the STRBD side of the motor. I am assuming it is in limp mode for some reason.
 

wbas1

Petty Officer 2nd Class
Joined
Aug 7, 2020
Messages
127
Update:
I found that the STRBD side Cylinder temp sensors connection was loose. I made a better connection and I once again have spark on the STRBD side.
 
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