1999 Yamaha 115 difficult to start

[brodmann]

My 115 is almost impossible to start. Runs great once it starts, but that takes forever. Lately, the only way to get it to crank and stay running is to press the button to disengage the shifter and set the handle at 3/4 throttle. It starts and revs up incredibly high. I pump the bulb up, push the choke while turning the key and it spins and spins and will cough once or twice now and then, but no start. Once it cranks and warms up a little with me pressing the choke when it starts to die out, it will idle fine and run all day at all different speeds. I've rebuilt the carburetor, replaced the fuel bulb, replaced plugs. It's driving me nuts. Any ideas would be greatly appreciated.

 

[99yam40]

does this thing have an electric choke?
does the choke work?

posting a complete model # helps others know what motor you have.
My C40TLRX (1999) has a prime start system that is automatic fuel enrichment, so no choke.
when You push the key switch in nothing happens, and it is not suppose to do anything.

 

[brodmann]

Yes, electric choke. Push in on key. It's working. It's an S115TLRX. As soon as I figure out which one of my 3 sons borrowed my compression tester, I'll do a compression test. Carbs recently rebuilt and plugs replaced (a couple of weeks ago. Ran great since then, but took a long time to start. When I get tired of choking and spinning, I'll usually end up blocking out the shift and opening up the throttle to about 3/4 full and it will fire up and rev really high. I gradually ease it down to idle and let it run a couple of minutes and it's fine all day. Yesterday spent a long time getting it to crank in the yard with water hooked up. Drove to the boat ramp an it took forever to start. Drove 45 minutes to an island to meet up with kids and grandkids on the beach and spent 4-5 hours there. Took forever to get it started again, and it shut off a couple of times while maneuvering around other anchored boats to get back in deep water. Every time it shut off, it took forever to get it going again. I'm wondering about ignition switch, coils, stator......, but none of that makes sense to me since it runs fine once started. It runs about 40 MPH at about 5700 RPM's which to me eliminates the possibility of low compression, faulty ignition parts, plugs...... I guess I'll dig into carburetors to check Idle circuit again.

 

[racerone]

Get the battery load tested.----Then take the starter apart for inspection.------

 

[brodmann]

I have 2 batteries. The batteries are capable of spinning the motor all day long. They basically do. It's not a battery problem.
Thanks though.

 

[99yam40]

Yes, electric choke. Push in on key. It's working. It's an S115TLRX. As soon as I figure out which one of my 3 sons borrowed my compression tester, I'll do a compression test. Carbs recently rebuilt and plugs replaced (a couple of weeks ago. Ran great since then, but took a long time to start. When I get tired of choking and spinning, I'll usually end up blocking out the shift and opening up the throttle to about 3/4 full and it will fire up and rev really high. I gradually ease it down to idle and let it run a couple of minutes and it's fine all day. Yesterday spent a long time getting it to crank in the yard with water hooked up. Drove to the boat ramp an it took forever to start. Drove 45 minutes to an island to meet up with kids and grandkids on the beach and spent 4-5 hours there. Took forever to get it started again, and it shut off a couple of times while maneuvering around other anchored boats to get back in deep water. Every time it shut off, it took forever to get it going again. I'm wondering about ignition switch, coils, stator......, but none of that makes sense to me since it runs fine once started. It runs about 40 MPH at about 5700 RPM's which to me eliminates the possibility of low compression, faulty ignition parts, plugs...... I guess I'll dig into carburetors to check Idle circuit again.

Have you tried opening the throttle a little before you try turning to start and push in for the choke?
more fuel means it needs a little more air also.

 

[racerone]

Good luck with sorting it out.

 

[brodmann]

My middle son's father-in-law is a Yamaha Master Technician and his family has owned and operated a marina and boat repair shop for 3 generations! I did not know that. Today, my son described the problem to him. After bombarding my son with questions, he asked about fuel/water separator and when it was last replaced. I've owned this boat for 4 years, and have never replaced that! Since I don't use ethanol free gas, and haven't replaced this filter, he feels I have water/impurities/settlement in the gas. Seems mighty simple, but I'll let y'all know if that solves the problem.