1996 Suzuki DT75 no power under load

[weedonbt1]

I just recently bought a 24ft Weeres pontoon with a 1996 model DT75 suzuki outboard. Motor seems to run great and seems to have good throttle repsonse and idles pretty good. But when I get it out in open water and give full throttle it will only manage 2100 rpm and crawls at best. Like another post I read, it will run to 6K when not under load but just seems to have no power which is starange considering everything else checks out and Im not getting any alarms either. The last post the guy said it ended up being his oil flow sensor, but wouldn't that throw an alarm? Does anyone have any ideas? Thanks in advance.

 

[James R]

Re: 1996 Suzuki DT75 no power under load

Probably at least one cylinder is not functioning. This is usually the problem with your symptom.
Do you have good compression on all cylinders, when were the carbs last serviced, are the plugs old, are you getting sparks on all plugs,is the fuel pump delivering,is there a blockage in the fuel line.

 

[weedonbt1]

Re: 1996 Suzuki DT75 no power under load

Yes all cylinders are hitting good. If one wasn't firing at all the motor either wouldn't run or it would have one hell of a noticeable hiccup. This motor starts, idles and will respond like a new motor. I have even been in the water and put it in gear and got back by the motor and cracked down on the throttle linkage by hand and the motor responds immediately with noticeable pull but pushes up to 2100rpm and sits there. Im not talking about 2090 rpm's or 2150rpms...2100 rpms exactly almost as if it was electronically limited. but you barely tilt the prop out of the water and she'll run to 5k. Had a slight fuel leak, repaired that and had no change.... Someone stated something about timing advance. im gonna check that next, but Im getting so many ideas on what the problem could be that Im really at a loss.

I just don't understand, if the motor will start and idle fine, have amazing throttle response, and seem to have good force from idle to full throttle when in gear, why would it just stop powering once it reaches 2100 rpm? Not only that but only when it is in the water. I can put the engine in the water and leave it in nutral and rev it like a dirtbike and it reacts beautifully. I may have bad compression on one cylinder I guess but why is it only noticeable when it is under load? Wouldn't I notice it running bad even when in neutral?

 

[cousinabe]

Re: 1996 Suzuki DT75 no power under load

sounds like a fuel restriction.
check fuel pumps, filters, trash in carbs.

fuel flow usage is different in nuetral vs under load.