'09 Stratos 385 xf prop questions

[REW]

US,
You could swing by your dealer and have your tach checked.

This is an easy thing to do. Just have the dealer start up your engine in the tank, and they can put on a manual tach on the flywheel, and then they can compare the manual tach reading to the reading of your tach.

You really want to know for SURE the rpm that your engine is running.

The specs for a 2017 200hp Optimax:

https://www.mercurymarine.com/en/us/...specifications



You will note that the wide open throttle rpm is recommended to be 5000-5700. So, one might try to have their rig running at about 5500 rpm with a medium load.




Again, you want to be able to verify the actual prop hp on your engine with a good dyno test. If you do that test, and find that you have a good solid 200hp or better, you can then look at other issues.
But, if you find that you at the prop hp is much less than 200 hp, you need to have the motor issue resolved, so that you are producing the power that you are not getting, if the dyno test indicates that fact.






Be safe

[usmarine1]

Well it is 100% the engine. At 4450rpm wot the engine makes an intermitten chattering noise and the power cuts in and out as well. It sounds as if the engine is retarding or more specifically a cylinder isn't picking all the way up. Any thoughts would be great.

[usmarine1]

Well after disconnecting the fuel line and putting it in two gallons of fresh 87 octane no ethonal and putting the motor in a water tank without the prop it runs right up to the rev limiter of about 6200 which I didn't mean to do. I did however run it up to 5500 and lower for a few minutes and no issues at all. I hooked the fuel line up and ran it for a few more minutes and ran fine. I contacted the previous owner waiting to hear back. I put Quicksilver fuel treatment 1 in last night hoping it would help but I saw worse results today on the water. A friend said use stabilize it'll help. I'm a bit Leary of running the 30+ gallons of fuel through the engine but I don't know how to get rid of it. I can't try to run with the prop on or under load could that change my findings today?. While running at high RPMs the intermittent miss and power loss didn't happen. Does that mean squat since it's not real world application? Hoping to not make this an optimax nightmare

[REW]

US,
You indicated that you put in a couple of gallons of fresh fuel and ran your engine.
Does this mean that you have a separate fuel tank that you can connect to your engine?

If so, take a few gallons of fuel in the portable tank and run the motor on the lake under load with the fresh fuel and see how it goes.

If it is all right, the issue is the fuel.

A very simple way to remove the fuel, is to blow out the fuel or syphon the fuel out of the tank or a combination of the two procedures.

When I do this, I remove the squeeze bulb from my fuel line. Then, I add a long fuel line of a diameter that will slip over the existing boat fuel line. This line is long enough to reach the driveway to use in filling a portable container, like a fuel can or 5 gallon bucket.

Then, if you want to suck gas, you can suck the end of the fuel line and start a syphon going and syphon all of the fuel out of the tank. It will take a while but it will syphon by itself.

However, if you want it to be a bit more speedy, just use an air hose and a blow gun from an air compressor to put a "slight" bit of air pressure on the tank such that the fuel will start flowing out of the fuel line into the fuel cans.
It works best with a couple of folks. One person puts their hand over the vent on the fuel tank. The other person wraps a rag around the end of the air blow gun tube and then stuff the blow gun and rag into the fuel tank fill hole. As needed, modulate the blow gun to add "slight" pressure to the fuel tank and fuel system. Normally only a couple of psi are required to get and keep the fuel flowing out of the tank into the drain bucket or fuel container. Continue, until you are only getting bubbles out of the fuel line.

To burn off the fuel, just dump 5 gallons of fuel at a time into the tank of a vehicle, let it mix with the rest of the fuel in the tank and burn it off. Continue until all of the fuel has been burned off.

Take care