t25tlra wont star in morning

[zenchal26]

Got a t25tlra 4-stroke that wont start in the morning but after that it runs fine all day. I have replaced the fuel pump, rebuilt carb, and replaced the prime start solenoid. What else am I missing here?? Eng is on a pontoon boat and the fuel tank is above the eng.

[99yam40]

How can it run fine the rest of the day if it will not start in the morning?
does it start in the afternoon?
Does it have spark when it will not start?

Did you clean the carbs well and did you follow the manual to adjust everything after the cleaning?

[zenchal26]

Hard start in morning push the throttle fwd two or three times then it will start. This work because when the handle is pushed fwd the carb squirts fuel into itself like a car carb. Then after it starts it works fine the rest of day. every thing else is like it should be

[99yam40]

So, just hard to start 1st time of the day instead of will not start.

That motor has the prime start system on it and no choke, so as long as you are not lifting the fast idle lever when trying to start it cold , then I would think you passages in the prime start enrichment system are still having a problem. As it is suppose to enrich the fuel into motor until the heater closes off that system

[zenchal26]

yes prime start on eng, replaced solenoid, cleaned and replaced diaphram in carb. there is power to solenoid.

[robert graham]

Hard start in morning push the throttle fwd two or three times then it will start. This work because when the handle is pushed fwd the carb squirts fuel into itself like a car carb. Then after it starts it works fine the rest of day. every thing else is like it should be

I don't believe your carbs have throttle pumps like on automotive carb...Yamaha relies on enrichening by the totally automatic prime start...neutral throttle lever should be down/closed for starting. Are you pumping the primer bulb until firm before attempting to start motor? Try adjusting your starting procedure slightly. On my motor I crank on the starter about 3 seconds, then let off a few seconds, then the motor will start right up...Why?..who knows..just the nature of the beast, I guess?....Are your spark plugs good and clean?

[99yam40]

yes prime start on eng, replaced solenoid, cleaned and replaced diaphram in carb. there is power to solenoid.

No solenoid, the electrical device is a heater that gets power from the lighting coil while motor is running.
It warms up a wax pellet that expands and pushes the needle out a small amount and closes off the enrichment fuel flow.
Still think your passages have some plugging

At least that is how the prime start system on my C40TLRX works, I have never looked at a 4 stroke like yours


Robert,
Yes it does have the plunger to help with acceleration

[robert graham]

No solenoid, the electrical device is a heater that gets power from the lighting coil while motor is running.
It warms up a wax pellet that expands and pushes the needle out a small amount and closes off the enrichment fuel flow.
Still think your passages have some plugging

At least that is how the prime start system on my C40TLRX works, I have never looked at a 4 stroke like yours


Robert,
Yes it does have the plunger to help with acceleration

I just don't think there's any plunger/carb pump on my carbs...90C

[boats.net]

Four stroke engines have more of an acceleration problem than 2 stroke engines and most 4 stroke models do have an accelerator pump system of some kind but 2 strokes don't.
T25 does have plunger pump system.

[robert graham]

Four stroke engines have more of an acceleration problem than 2 stroke engines and most 4 stroke models do have an accelerator pump system of some kind but 2 strokes don't.
T25 does have plunger pump system.

Thank you for clarifying that...just couldn't see how I'd miss a pump on my carb all these years!