Engine wont go above 2200RPM

[mmwjr]

Duh now I see, I’m seeing the asphalt looking straight through the port on the other side.

[wiigelec]

Nice insulated screwdrivers! You in electrical?

[mmwjr]

Originally Posted by wiigelec

Nice insulated screwdrivers! You in electrical?

Yes I’m a EE.

[fester]

Huge thanks to Mike for pointers in fixing this. I always like to finish out threads and help the next poor soul that might encounters this.

So its fixed and it could be 1 of two things. The flame arrestor was FILTHY. So much so I could wipe the carbon off with my fingers at the side. Second, it could have been engine alignment. I could hear the starter motor struggling to move it by itself on first start.

First thing I did was service the outdrive. Impeller looked ok and changed it anyway with a new kit. New gear lube etc. Next up, did an engine tune up as it needed a service anyway.

• Spent about 6-7 hours aligning the engine using the precision alignment tool... as best I could - this would be done in a fraction of the time if I had a second person!!!
• Spark plugs - changed gap to spec
• Spark plug cables
• Distributor cap
• Rotor
• Oil
• Oil filter
• Fuel filter
• Thermostat - old one was slightly rusted and corroded
• Full can of Power tune - the amount of carbon that fired out the back after the 15 minute wait was UNREAL!

Pleased to report its now like a rocket and my engine has been under performing this whole time.. I now get below the 4800 MAX WOT limit on the engine with the same prop. I was previously getting 4300 or 4400.

I hope this helps other people. Learned alot and thanks again to Mike (mmwjr)/this forum for all your help and support as always!

[Phillbo]

Thanks for the follow up... Most people don't do that !!

[mmwjr]

We’re all here to contribute as much as we can and glad to hear when folks resolve their issues. Payback is knowing you’ll be able to enjoy the rest of the season. Lots of valuable information from all members.

[fester]

Had to report this.. While out on the lake over the weekend, engine started to do the same thing with more people on the boat (4 adults 4 kids). It wouldnt go above 3200RPM..

I took the flame arrestor off and it was filthy again.. Ran the boat without the flame arrestor and gladly went up to 4800RPM. Cleaned the arrestor with carb cleaner and not a bother on it the next day.

Once again Mike (mmwjr) you are spot on.. Thank you ! I wonder what is causing so much carbon to build up to clog it?.. or is this consider normal after about 30 hours of use?

[mmwjr]

Excessive blow by. Perform a compression test.

[mmwjr]

I got you PM with the compression data; number 6 is on the lower end but not enough to cause any significant blow by. Post a picture of the engine showing how the breather hoses are attached to the flame arrestor. You can try disconnecting the hoses to see if that stops the soot build up. How long does it take for this to occur?

[another todd]

I know this thread is over three months old, but it sounds to me that it is not running on all 6 cylinders. Could the cold bank not be firing?

[bparisi]

I had similiar issue on my 3900 scr with cummins engines. I understand it's apples oranges but my issue was the alternator. Just a 411 hopefully it helps