Yamaha F15SMHA 2016 Prime start questions

jdor

Recruit
Joined
Mar 16, 2023
Messages
2
Hey all,

I've got a new to me Yamaha 15. Previous owners had the engine serviced back in January and they hadn't used it since as they only use the engine during summer for their dinghy.

Now that I am the owner, it ran pretty well for the first couple weeks, but after using it daily(to dinghy to/from my boat on a mooring ball), i've started to realize that the engine absolutely hates cold starts. I'm thinking it might be the prime start based on what i've researched today.

Cold for me is in the 30's as I am in Seattle. I was thinking of pulling the prime start and testing how much travel is in the arm & how long it takes. Does anyone have any exact numbers in travel over time for this? I can't seem to find anything on that.

As for cleaning the passage way - can I spray carb cleaner in it from where the prime start is on the carb?

AS for the symptoms we are seeing. It usually starts up on the second or third pull, but after maybe 30 seconds it'll die. From that point, it takes a good 5 pulls at least to get it back up and running but again, it lasts maybe 30 seconds. Third time or fourth it'll fire up and stay running but sometimes it can take 10 pulls or more to get it to fire. Once it's warmed up a bit, it runs without troubles. My neighbors Honda 15 with similar prime start has ZERO problems and i haven't seen many complaints about this with Hondas. Wonder if theres a difference in parts between the two engines?
 

boscoe99

Lieutenant Commander
Joined
Aug 22, 2013
Messages
1,968
Travel distance is available. I have not seen travel time published. Time should not matter. The longer the time for the pin to move the longer the motor will be running a bit on the rich side. Which is what is needed to help start a cold motor.
 

boscoe99

Lieutenant Commander
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Aug 22, 2013
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1,968
I would suspect that the carburetor is in need of a thorough cleaning. Completely dismantled and cleaned in a heated ultrasonic cleaner. All orifices and passageways verified to be free and clear.
 

boscoe99

Lieutenant Commander
Joined
Aug 22, 2013
Messages
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Yams outnumber Honda's by probably hundreds to one. You are going to be hearing more about Yam problems simply because there are more of them in service.
 

boscoe99

Lieutenant Commander
Joined
Aug 22, 2013
Messages
1,968
Have you tried using the accelerator pump to add a bit of extra gasoline at cold start?
 
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