Penta 5.0 Stuck at 2000 rpms

[riden]

So my son has a Campion Allante 595.

Volvo Penta 5.0

He is no mechanic and a boating noobie. I’m a decent mechanic, and pretty familiar with my fishing boat. Not inboards

This is his 3rd year with the boat. Ran great first year. He screwed up winterizing it, and didn’t stabilize the fuel for winter.

Next year it ran poorly. I assumed the carb was gummed up. It started fine, sounds good, but under load would not rev higher than 2000 rpms. I added a very rich amount of Seafoam and it ran much better that day. Not 100%, but as it bogged down temporarily every now and then. But he could pull a huge tube, all seemed good.

He said it never ran that well again and he worked a lot last summer and never had a lot of time for the boat.

This year, exact same problem. I took off the carb and had it professionally cleaned. Didn’t help. Starts good, idles well. In neutral, will rev to 4000 rpms and sounds good

In gear. 2000 rpms is it.

While the carb was getting cleaned I took a look around Distributor cap definitely needs to be replaced. I have no spark plug socket, but I bet they need to be replaced too. We are camping at the lake right now.

Would bad plugs and distributor cap cause this? That’s gonna be job #1. I cleaned the connections on the distributor cap, as they looked well worn.

Any advice or ideas I may be missing would be appreciated.

 

[kenny nunez]

Changing the cap,rotor and plugs might help. Just to be sure try using a 6 gallon out board tank connected to the fuel pump to by-pass the fuel tank . Quite often the problem is in the suction tube in the tank, there is usually a very fine filter in the tube that gets stopped up.

 

[Scott Danforth]

yes, bad plugs, cap, rotor and a dirty carb would cause it

there is no mechanic in a can. the carb should be torn down and cleaned.

 

[riden]

yes, bad plugs, cap, rotor and a dirty carb would cause it

there is no mechanic in a can. the carb should be torn down and cleaned.

Maybe not in a can....... but I took it to a small engine mechanic who used an ultrasonic cleaner.

 

[Scott Danforth]

never had luck with an ultrasonic cleaner on the internal passages. I have always had to pass a wire or fishing line thru them. many times I have to use my pin-drill vice and drill the crud out.

 

[riden]

never had luck with an ultrasonic cleaner on the internal passages. I have always had to pass a wire or fishing line thru them. many times I have to use my pin-drill vice and drill the crud out.

I really expected the main jet to be the issue.

Mechanic insists he ensured the jets were clean

 

[Scott Danforth]

if its a holley, check the metering block

 

[riden]

Problem solved.

Thanks for the help guys!!!!

 

[kenny nunez]

What was the problem? And what cured it?