Brand New DF30A won't go over 3000 RPM

[trizzle]

Hey guys! Got the boat on the water for the first time today. I let it sit for 15 minutes idle, for it up to 3000 rpm to where I wanted to fish and trolled around for 4ish hours. The wind picked up and decided I needed to head in. Like it says in the title it would only go 3000 rpm 6 miles per hour full throttle. Any ideas?

[trizzle]

I thought I'd add it's a 76 13 ft whaler

[trizzle]

I'm on a mobile and don't see how to edit a post. I'm pasting what I posted on another forum.

I bought a DF30A remote control model and got it on the water for the first time today. I let it sit for 15 minutes idle, got it up to 3000 rpm went to the area to where I wanted to fish and trolled around for 4 hours. The wind picked up and decided I needed to head in. Like it says in the title it would only go 3000 rpm @ 6 miles per hour full throttle. Any ideas? I want to give as much context that I can so I can figure this out. As you can imagine I was pretty bummed out to have this experience. I have a Suzuki tach with all the system lights. There were no lights that came on our any warning noises. I looked in the manual and it gave a couple reasons of limitation of 3000 rpm but involved warning sounds and lights. Other than that I was pretty pleased. It started right up and trolled between 1-2 mph. I hope I can achieve at least 20 mph in case is sketchy scenarios like today. I've got it mounted to an old 13 Boston whaler sport.

Is there a safe way for me to test the rpm without putting it back on the water?

[2014DF25ARS]

An obvious guess, if it's the first time you've run it, is that the throttle cable is not adjusted correctly, and the motor simply isn't seeing the request for full throttle. I have a DF25A = essentially the same motor, and I experienced a problem around 200 hrs, where my engine would not run above about 2000 RPM, with no error indications. Eventually I fixed it by replacing the high-pressure fuel filter. Not the blue one, but a smaller black one between the VST and the high-pressure fuel pump. But I can't imagine that filter would be clogged on a new motor.

[trizzle]

An obvious guess, if it's the first time you've run it, is that the throttle cable is not adjusted correctly, and the motor simply isn't seeing the request for full throttle. I have a DF25A = essentially the same motor, and I experienced a problem around 200 hrs, where my engine would not run above about 2000 RPM, with no error indications. Eventually I fixed it by replacing the high-pressure fuel filter. Not the blue one, but a smaller black one between the VST and the high-pressure fuel pump. But I can't imagine that filter would be clogged on a new motor.

The throttle cable is the first thing I thought it could be when I was experiencing it on the water. But as I thought about it there is so little room for adjustment. I'm going to check it out but don't really think is the issue.

[trizzle]

I just checked and the remote controls do indeed push the throttle all of the way down when controls are pushed all of the way down. I was checking the control position from where I was achieving 3000 rpm vs all the way down and the lever on the throttle significant in difference. I was probably 3/4 or less when I was trying to be at 3000 RPM.

[Harper]

MIght have a neutral safety switch out of adjustment. If I recall correctly, the RPMs are limited around 3000 if the motor thinks it's in neutral.

[trizzle]

MIght have a neutral safety switch out of adjustment. If I recall correctly, the RPMs are limited around 3000 if the motor thinks it's in neutral.

I checked the neutral switch as I was going between neutral and going into gear. It seemed to work mechanically, I could see a little solenoid engage and disengage. I don't know if it would matter but possibly does. The large harness that plugs into the motor from the control box wasn't pushed in completely. Only reason I don't know if this will be the fix is because every other function was working fine. I'll let you guys know if this fixes it.

[2014DF25ARS]

One thing you can do to investigate the neutral safety switch theory (which is a good one) is to use the "fast idle" lever. On my DF25A, which is working normally AFAIK, if I raise the fast idle lever on the remote control with the engine in neutral, the RPM will increase until the engine hits the neutral rev limit (3000 RPM?). At that point my motor starts running very rough, dropping RPM then catching up again, then dropping, etc. Somewhere I got the idea that the way the motor enforces this RPM limit (and/or the max rev limit) is by cutting the spark to one of the three cylinders. So when my engine is exceeding the allowed RPM it runs like poo. Very rough.

[Moonlighter]

One thing you can do to investigate the neutral safety switch theory (which is a good one) is to use the "fast idle" lever. On my DF25A, which is working normally AFAIK, if I raise the fast idle lever on the remote control with the engine in neutral, the RPM will increase until the engine hits the neutral rev limit (3000 RPM?). At that point my motor starts running very rough, dropping RPM then catching up again, then dropping, etc. Somewhere I got the idea that the way the motor enforces this RPM limit (and/or the max rev limit) is by cutting the spark to one of the three cylinders. So when my engine is exceeding the allowed RPM it runs like poo. Very rough.

In neutral the ecu cuts spark, limits spark advance and restricts fuel supply to prevent the engine exceeding the limit. Very much like a race car that is on the pit lame rev limiter.

[tsturm]

I'm on a mobile and don't see how to edit a post. I'm pasting what I posted on another forum.

I bought a DF30A remote control model and got it on the water for the first time today. I let it sit for 15 minutes idle, got it up to 3000 rpm went to the area to where I wanted to fish and trolled around for 4 hours. The wind picked up and decided I needed to head in. Like it says in the title it would only go 3000 rpm @ 6 miles per hour full throttle. Any ideas? I want to give as much context that I can so I can figure this out. As you can imagine I was pretty bummed out to have this experience. I have a Suzuki tach with all the system lights. There were no lights that came on our any warning noises. I looked in the manual and it gave a couple reasons of limitation of 3000 rpm but involved warning sounds and lights. Other than that I was pretty pleased. It started right up and trolled between 1-2 mph. I hope I can achieve at least 20 mph in case is sketchy scenarios like today. I've got it mounted to an old 13 Boston whaler sport.

Is there a safe way for me to test the rpm without putting it back on the water?

How water soaked is the foam in your old whaler? Go weigh the boat on the trailer & look up the old spec. for boat weight & subtract trailer weight. Or try a smaller pitch prop.

[trizzle]

I took it back out on the water tonight. It goes about 3300-3400 rpm in forward gear. In reverse it got up to 6000 rpm easily before I stopped. Does that sound like anything obvious?

[trizzle]

In neutral the ecu cuts spark, limits spark advance and restricts fuel supply to prevent the engine exceeding the limit. Very much like a race car that is on the pit lame rev limiter.

It doesn't run rough at the 3300 rpm for me, just gutless. I pulled up the fast rev in neutral and that definitely ran rough.

[trizzle]

Moonlighter you seem savvy and helpful. Do you have any suggestions? I'm at a loss.

[Moonlighter]

Nope, got nothing else to add here ....