Having trouble running at full throttle.

C

chub1

Recruit
Joined
Dec 7, 2001
Messages
2
Hello everybody I own a 1997 merc mriner magnum.It is having trouble running at full throttle.I know what your thinking carbureators.I have already had the carbs cleaned out twice since I bought it back in september.It ran fine for the two times I took it out after that but now it's back<br />to it's old self.The only thing is is when the carbs were uncleaned it used to pulse <br />back and forth but now it runs at1/4 to 1/2<br />throttle steady with no bogging or pulsing at all.Please help me!!!Oh and by the way so you don't think that it is getting gunk out of the gas tank After I had the carbs cleaned I bought a new fuel tank,filter and line. :mad: :confused:
 
B

Backlash

Chief Petty Officer
Joined
May 16, 2001
Messages
586
Re: Having trouble running at full throttle.

Hey Prodigal Son,<br />Did you check the fuel pump?<br />Backlash
 
T

Trent

Captain
Joined
Nov 17, 2001
Messages
3,333
Re: Having trouble running at full throttle.

What happens if you squeeze the fuel bulb when it starts acting up? If the problem goes away..Do as backlash said and install a diaphram kit in the fuel pump.
 
G

Grant Ingle

Seaman Apprentice
Joined
Aug 17, 2001
Messages
49
Re: Having trouble running at full throttle.

When having the carbs rebuilt you should always opt to rebuild the fuel pump, also. Are you sure that all the fuel lines are tight to their fittings and that there are no cracks or kinks in the fuel lines under the cowling? Anytime the fuel system can draw air instead of gas it will do so. This will usually be noticeable above half throttle as the motor begins to starve for gas. Also check to see if fuel leaks excessively anywhere when you prime up the fuel bulb. Bypass the check valve on the fuel fitting with a small screwdriver and take a fuel sample just to make sure there is no water in the gas. ;)
 
R

Rex

Chief Petty Officer
Joined
Aug 12, 2001
Messages
424
Re: Having trouble running at full throttle.

I don't remember who it was now but<br />they had the same problem.<br />He said he run the engine without the<br />cover on it and it run fine.<br />He said once it could the air it run great.<br />Just a thought.<br />Rex A.
 
R

Rex

Chief Petty Officer
Joined
Aug 12, 2001
Messages
424
Re: Having trouble running at full throttle.

Ask RED SKY about this I think he<br />might remember this.
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Having trouble running at full throttle.

Howdy, Prodigal son. I think Backlash and Grant have you on the right track, at least 'til you have more info.<br /><br />Good luck.<br /><br />Red sky at night. . .<br />JB :)
 
M

mbb

Petty Officer 2nd Class
Joined
Apr 20, 2001
Messages
176
Re: Having trouble running at full throttle.

the pulsing bothers me, but you need to check fuel pump as mentioned above. Put clear tubing on fuel pump outlet and look for bubbles in fuel, there should be none. If there are the leak gets worse with rpm/suction and the fuel pump starts losing prime. rebuild the fuel pump anyway, its dirt cheap.
 
M

MERCMAN

Seaman
Joined
Oct 13, 2000
Messages
73
Re: Having trouble running at full throttle.

YOU SAID IT RAN FINE THE FIRST TWO TIMES OUT NOT SAYING IT'S NOT FUEL BUT IF A FUEL PUMP IS WEAK IT'S GOING TO RUN BAD ALL THE TIME AND NOT RUN GOOD THEN RUN BAD SOUNDS LIKE TO ME YOU HAVE IGNITION PROBLEM LIKE ONE CYLINDER DROPPING FIRE THEN COMING BACK.
 
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