Suzuki DT55 low rpm

Hey there, new to the forum. I have seen this before but havent seen the fix. While running on plane my DT55 dropped power and runs about 3000 rpm. Now it will not run above that. RPMs are fine out of the water and not under a load. I do have the owners manual. I replaced my oil filter and that wasnt it. The oil pump seems to be pumping fine. Oil level is also fine and the oil level light shows the same. I tried to reset the oil level reset switch (on the side of the engine). It doesnt budge. I replaced the water pump. Still same problem...BUT I noticed that the tell tale is not producing a steady stream. It doesnt seem to be overheating. The red water light comes on when I start the engine and the alarm has a steady buzz and then shuts off. <br /><br />Q 1: Will the water/coolant sensor cause the lower rpm?<br /><br />Q 2: If so, is there a reset switch? I cannot find one and the manual doesnt mention one for this model.<br /><br />Q 3: is there a particular place in the coolant lines that this engine typicaly clogs?<br /><br />Q 4: If it was originally an oil problem and I have a bad reset switch. Can I "jump" the oil level reset switch to reset the system?<br /><br />Q 5: Does the engine need to be running to reset any of these systems?<br /><br />Other notes: 1998 DT55 with a jet drive pump, 17 ft aluminum simi V. Engine runs smooth and starts fine.<br /> <br />Help, <br />Up a creek without power.<br /><br />Neil

Re: Suzuki DT55 low rpm

Check to see if you are running on all cylinders. You may have dropped a cylinder and something as simple as a new spark plug may be all that is necessary to get it going. Ground each spark plug one at a time and see which cylinder isn't pulling its weight, that's the one to look at.

Re: Suzuki DT55 low rpm

I should have mentioned that. Engine is firing on all 3, compression is in spec on all 3. All within 3 lbs. of each other. Engine runs perfect except a rev limiter of some sort kicks in at 3000 rpm, but does not kick in unless it is under a load (in the water).

Re: Suzuki DT55 low rpm

I should have mentioned that. Engine is firing on all 3, compression is in spec on all 3. All within 3 lbs. of each other. Engine runs perfect except a rev limiter of some sort kicks in at 3000 rpm, but does not kick in unless it is under a load (in the water). I also have a water hose hooked up to the intake (high pressure) when running out of the water. I may be answering my own question here. Must be something to do with water flow. But I cant find a problem.

Re: Suzuki DT55 low rpm

take a flash light and carefully check the muffler tube in the jet. it usually corrodes at the pump unit and if it gets a hole in it you will get a powerloss just like you describe.

Re: Suzuki DT55 low rpm

When you say "muffler tube", do you mean the inner tube/pipe of the outlet on the jet drive? I think it is stainless steel and about 2 inches in dia.? Or are you talking about the excaust port above it on the lower unit? Or am I way off here?

Re: Suzuki DT55 low rpm

I used to own a DT55 and occasionally under load the engine would seem to bog down like it was running on one less cylinder. Problem would come and go but seemed to come up when pounding waves or under hard acceleration. Turned out to be a saturated float switch in the powerhead which activates the rev limiter. The switch kicks in the rev limiter when there is little or no water flow in the power head and is designed to limp the engine along and protect against cooking the engine. The sensor/switch is located on the top right side toward the rear of the powerhead and has a single wire coming from it. If I remember correctly it requires only a philips screwdriver to replace it.<br />Bet replacing it solves your problem.

Re: Suzuki DT55 low rpm

I pulled the water level sensor/switch and hooked an ohm meter to it and tested fine. Stuck it in a bucket of water and the float rises as it should. Also pulled the T-Stat and it seems to work fine. I also checked the oil level/alarm reset switch and it seems to be fine also. I cannot find any type of reset for the rev limiter. Any idea how the rev limiter works? The throttle is wide open. Is the rev limiter a function of the automatic timing?