1999 90 hp Yamaha prime start

S

surfbass

Cadet
Joined
Jan 17, 2004
Messages
25
From searching this site I see my motor has the primer instead of a choke for cold starting. Apparently it does not work because it is very hard to get started on the first crank of the day. It also has a red lever beside the carbs for fuel adjustment. By flipping this red lever the motor fires right up as if it had been choked. After it starts I flip the lever back and it cranks easily the rest of the day. My question is; is this hurting anything and is there any reason that I should not do this?
 
Dunaruna

Dunaruna

Admiral
Joined
May 2, 2003
Messages
6,027
Re: 1999 90 hp Yamaha prime start

The little red lever is an 'emergency start'. Basically, it bypasses the idle circuit in the carbs.

What you are describing is quite common and is caused by incorrect starting technique or the carbs/primer solenoid are gummed up (the latter is very common).

Cold starting technique should be - Pump the bulb until hard, lift the fast idle lever, crank motor for a few seconds, lower the fast idle lever, crank and start (hopefully!). The primer system should automatically hold a fast idle and then (automatically) reduce to normal idle, this should take a few minutes.

If the starting technique does not work, time to rebuild the carbs and perform maintenance on the fuel system in general.
 
R

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 1999 90 hp Yamaha prime start

with prime start DO NOT raise the fast idle.
it usually defeats the prime start.
clean the carbs,check the primer solinoid for proper rod extension as per your service manual,check the prime start pump diaphram,check valves and the oring on the bypass shaft.
put it all back together correctly and play.
a quote from the Yamaha tune-up spec book.
1992-2005 90 hp including B90 and C90.
" prime start model- DO NOT use warm up lever when starting".
thats why I always reccomend reading the operators manual for how to operate the gear you have.
as far as using the manual bypass,wont hurt anything but its a hassle and your motor is trying to tell you its sick. heal it.
 
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