premium gas a solution to lean sneeze?

2rz-fte

Seaman
Joined
Dec 16, 2008
Messages
70
so i have another thread about my 96 88hp 'rude having a lean sneeze at idle. when i put it into gear (F or R) the rpm drops a little more and then when it sneezes,misses, backfires the motor doesnt have enough rpm in it to catch itself and itll die.

if this infact lean sneeze, would running a premium 91 octane gas help (or even solve) the issue?

my mentality is that if i have a predetonation problem then running a higher octane gas should remedy it.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: premium gas a solution to lean sneeze?

clean and rebuild carbs, idle speed has to be set in the water, with the motor in gear.

the motor wants 87 Octane, not high grades.
 

2rz-fte

Seaman
Joined
Dec 16, 2008
Messages
70
Re: premium gas a solution to lean sneeze?

just talked to the mechanic and when he set the idle it was in his "tank". my motor sits a bunch lower in the water as compared to his "tank". so i just gotta adjust the idle screw while im in the water at the launch.

i didnt wanna touch anything on the motor because ijust had the annual maintenence done to it, so i wanted to talk to the mechanic before i started touching stuff and voiding all the work he did.

good guy, very highly recommended, hes actually gonna show me how to adjust it so when i get on the water i can do it properly.

guys name is John at Lees' Marine service in cerritos, ca.
 

countvlad

Chief Petty Officer
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Jun 29, 2009
Messages
439
Re: premium gas a solution to lean sneeze?

just talked to the mechanic and when he set the idle it was in his "tank". my motor sits a bunch lower in the water as compared to his "tank". so i just gotta adjust the idle screw while im in the water at the launch.

i didnt wanna touch anything on the motor because ijust had the annual maintenence done to it, so i wanted to talk to the mechanic before i started touching stuff and voiding all the work he did.

good guy, very highly recommended, hes actually gonna show me how to adjust it so when i get on the water i can do it properly.

guys name is John at Lees' Marine service in cerritos, ca.

and your question is? haha
 

jtexas

Fleet Admiral
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Oct 13, 2003
Messages
8,646
Re: premium gas a solution to lean sneeze?

if the exhaust relief ports (two holes on the aft side of the motor below the cowl) are submerged, you might well always have a hard time at idle. Consider raising the motor, if you can without losing water pressure at high speed.

Agree that higher octane should help resolve predetonation but that's not a high-compression motor, it's designed for 87 octane, so if you do have symptoms of preignition, look elsewhere for the cause...carbon buildup in the cylinders, for example.
 

2rz-fte

Seaman
Joined
Dec 16, 2008
Messages
70
Re: premium gas a solution to lean sneeze?

and your question is? haha

i kinda answered my own question

if the exhaust relief ports (two holes on the aft side of the motor below the cowl) are submerged, you might well always have a hard time at idle. Consider raising the motor, if you can without losing water pressure at high speed.

Agree that higher octane should help resolve predetonation but that's not a high-compression motor, it's designed for 87 octane, so if you do have symptoms of preignition, look elsewhere for the cause...carbon buildup in the cylinders, for example.


well, im gonna try to adjust the idle and if that doesnt solve it ill seafoam it in efforts to rid some of that gunked on carbon from years of use. also, it was just the first trip of the season. when i start taking out more often and leftover gunk should be burnt out.
 
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