150 Optimax lost power

[Charger69]

Serial# 1B826299.
Was out last weekend, boat ran great till end of day. Went to leave a cove after fishing for awhile and the motor would not rev up like normal, very sluggish. Motor started like normal and idled normal. Was just slow to rev up, boat finally did get on plane but even then was down on power, would not go up to normal RPM. I had no warning horn, I have vessel view, temp was normal, idle RPM was normal, and there were no fault codes. 2 other things to note: last summer one time when heading back to the ramp, the boat lost RPM around 400-500 RPM and some mile an hour. This lasted about 20-30 seconds and then went right back to the RPM and mile an hour we were going, never did it the rest of the year and has been fine this year till last weekend. 2nd thing, have noticed the idle has a slide surge, you can hear it and see the tach needle move up and down slightly, this is in neutral with no load. I am wondering what your thoughts are on this? Appreciate all help, thank you.

[JOE54]

check for fuel in air side of injection system

[EuropeanAM]

Also check basics: Compression, SPARK test, Air/Fuel Pressures.

Make sure you are up to date on ALL Recommended Annual Maintenance for Optimax Engines (see FAQ section).

[Charger69]

check for fuel in air side of injection system

Will do

[Charger69]

Also check basics: Compression, SPARK test, Air/Fuel Pressures.

Make sure you are up to date on ALL Recommended Annual Maintenance for Optimax Engines (see FAQ section).

Performed Annual (100 hrs) maintenance a couple months ago, heading back down to the lake this weekend and will check compression, can a spark test be performed by using a timing light on each plug wire?
Thank you for the help

[leonreno]

Yes to timing light

[JOE54]

betting on another tracker valve

[Charger69]

I wanted to update, was able to get down to the lake this weekend. Checked compression. Lowest cylinder was 117, the others are between 118-120. Was not able to check the fuel pressure and air pressures in the rail myself, but the dealer down there did and said they were both in the correct range. They also checked my coils and said they were fine, they tightened a ground that was not very tight. They asked me to take the boat out and try it. We took it out yesterday to test and fish some, boat started fine, took off out of the no wake fine. Fished 1st location for about 25 minutes. Boat started fine and ran fine for a couple miles or so. I was running at 4700 RPM at 44 MPH when it acted up. It dropped 500 RPM and 5 MPH, I took just a few moments to look at the gauges (20 seconds) and pulled the throttle back some, then gave it a little throttle it sounded OK and did not feel like a miss, so I gave it more and the RPM came back boat was back to running normal and did not act up the rest of the morning. Made 2 more stops , fished boat ran fine with no issues. I wanted to let you know, when we loaded the boat back up. We pulled the cover and I had read about checking the schrader valves on the rails. Mine has both valves on the port side rail, one at the top facing up and the other is in the middle of the rail facing out. I pushed on the top one and some gas came out, I did not hear any air. I pushed on the one in the middle of the rail and it shot a bunch of gas out. I did not think gas was supposed to come out of both of them? Sorry about being so long winded, and again, thanks for the help.

[JOE54]

correct its not ,need to find out how its getting in rails

[Charger69]

correct its not ,need to find out how its getting in rails

would the tracker valve diaphragm cause this or the fuel regulator diaphragm? Also could either one of these diaphragm's cause the intermittent problem I'm having?

[EuropeanAM]

Either (start with TRACKER valve... if torn or damaged, stop THERE and replace).

Also ANYTHING that causes an air leak will cause fuel on the air side.

Keep in mind: There SHOULD normally be fuel VAPOR on the air side. There should NOT be "liquid fuel".

[Charger69]

Thank you, the fuel that shot out of the one valve located in the middle of the rail, was liquid fuel, shot out about 2 foot or so, glad I was standing off to the side!

[EuropeanAM]

Was the engine OFF?

[Charger69]

Yes, the engine was not running.

[EuropeanAM]

Always make sure to relieve the air pressure FIRST (as that will drop the fuel pressure considerably).

[Charger69]

OK, I would like to clarify a couple of things. My motor does not have a schrader valve on each rail. Both of my valves are on one rail (port side). One on top and one in the middle. The one on the top, should have had just fuel coming out of it and no air (correct)?
And the top one when pushed is checking the tracker valve (correct)?
The one below, in the middle of the rail, when pushed should have had just air coming out, not liquid fuel, this is the valve for checking the fuel diaphragm (correct)? I pushed the one on top 1st and had fuel (no air) come out, did not come out under much pressure. I then pushed the one in the center of the rail and liquid fuel came out of it under a lot of pressure, fuel shot out 2 foot or so. Also you had asked if the engine was running, it was not running. Should I have had it running when checking this? Or was it OK to check with the engine shut off.
Just trying to make sure I'm doing things correctly, boat is south of me 135 miles, thank you

[EuropeanAM]

Engine should NOT be running. Key should be OFF.

These ports are NOT for "checking the tracker valve" or for "checking the fuel pressure diaphragm". They are for a set of Diagnostic GAUGES to connect to the engine.

Fuel pressure is the upper port, Air pressure is the LOWER port.

If you had massive amounts of liquid fuel at the lower port, check the TRACKER valve FIRST.

[Charger69]

Got it, will do, thank you, I appreciate it.