140 Mercruiser restricting after 2500 Rpm's

[Primo321]

Hello all I have been working on my 69 Mark Twain v sonic for over a year. So far it has Rebuilt engine 140hp Mercruiser I/O, new floor/carpet, new instrument panel to name a few.

Had her out this weekend for the first time this year and everything was running smooth! until, i brought her in for a short break and headed back into tha lake, when i felt a hard stall in the engine. After that she didnt want to take any gas. It feels like it is being restricted somehow when trying to go above 2500 rpm.

The engine will run up to full RPM while in neutral.

I noticed a small gas leak from the copper line to the hose, but im not sure if this has anything to do with my problem.

Any help would be appreciated.

See attached picture more to come!

 

[Blk-n-Blu]

Re: 140 Mercruiser restricting after 2500 Rpm's

Gas leak = BOOM it is possible your sucking air into the fuel system and getting a lean condition.

 

[Primo321]

Re: 140 Mercruiser restricting after 2500 Rpm's

Thanks, I hope its an easy fix. I have replaced nearly everything else, im hoping that this can be easy. Do you think I could have done any serious damage? Like I said the engine will run up to full rpm while in neutral, so Im hoping thats a good sign.

 

[Bifflefan]

Re: 140 Mercruiser restricting after 2500 Rpm's

Thanks, I hope its an easy fix. I have replaced nearly everything else, im hoping that this can be easy. Do you think I could have done any serious damage? Like I said the engine will run up to full rpm while in neutral, so Im hoping thats a good sign.

Seroius Damage? not to likely.
Neutral means nothing. it only takes a bit of gas and virtully no timing to get revs with no load.
Amoung the list of items replaced, was one the carb, fuel pump, lines and filters?
Got water in the gas? Vapor locking? Timing set right? Timing advance curve correct?
In the Merc section there is an Adults only post. In that there is a post about tune ups. try starting there.

As a side note, Gotta love that dashboard....

 

[Bifflefan]

Re: 140 Mercruiser restricting after 2500 Rpm's

After a re-read of your post im leaning toward the vapor lock or water in the gas.

 

[Bondo]

Re: 140 Mercruiser restricting after 2500 Rpm's

Like I said the engine will run up to full rpm while in neutral, so Im hoping thats a good sign.

Ayuh,... Revin' a motor to Redline in Neutral, No Load, can do more Damage than anything,...
And,...
It Proves NOTHING.......
With 1/2 the sparkplugs out, it'll Rev to the Moon in Neutral, No Load,...

Fix the Known problems,+ move on from there....

 

[Primo321]

Re: 140 Mercruiser restricting after 2500 Rpm's

Thanks for the tips. I will make sure to keep you all posted on the outcome.