carbs?

[razzor]

1992 mercury, 75horse, serial #0d165408.

starts great, idles great, runs great up to 3100 rpms,
thats it, I can't get anymore out of it than that, doesn't stall or sputter or anything like that, just won't go past 3100rpms in gear, in N will rev up as high as you want to.
rebuilt fuel pump, check and/or replaced all lines for gas and good flow everywhere.
Are my carbs trashed?
Top carb responds well to adjustments,
2nd carb did but is barely responding now
bottom carb has no response at all to adjusting the mixture screw.
Boat sat for 2 years and Im amazed at how well it cleaned up and runs, untill you hit 3100rpms.

I did all the stardard stuff like seafoam, gumout, got rid of all the wasp and muddabbers nest, compression check was good, 135-128-125 good spark and new prop hub, no leaks anywhere,
whats next? thanks guys, thanks alot, Razzor

 

[Bob_VT]

Re: carbs?

Spark and timing. If it sat for two years something is or could be corroded. Check your timing. Once it is hitting a certain spot the timing is preventing further advance under load. You might be lacking spark in 1 or 2 cylinders as the timing advances. Even a motor with a missing cylinder will rev up in Neutral.

If the carbs are not responding then the low speed circuits are clogged and the carbs could probably stand a re-build.

 

[Laddies]

Re: carbs?

The first thing you need to know is the idle adjustment screws have nothing to do at all with high speed preformance. The second is that seafoam and gumout type products are not a fix all, they will help in nsome cases but won't rebuild your engine as some on this forum expound. There is no better way anwser to a dirty fuel system than to tear it apart and clean it. and yours sounds like it needs cleaning, avoid damageing your engine running it around with a lean condition trying the wonder products (wondering why they aren't working)

 

[razzor]

Re: carbs?

The first thing you need to know is the idle adjustment screws have nothing to do at all with high speed preformance. The second is that seafoam and gumout type products are not a fix all, they will help in nsome cases but won't rebuild your engine as some on this forum expound. There is no better way anwser to a dirty fuel system than to tear it apart and clean it. and yours sounds like it needs cleaning, avoid damageing your engine running it around with a lean condition trying the wonder products (wondering why they aren't working)

 

[razzor]

Re: carbs?

Thank you Gentleman, will do.
razzor

 

[bgfloyd]

Re: carbs?

how do you clean the 3 carbs on 2000 75 hp mercury?