40 hp 2 stroke issues

[bassfam334]

04 40 hp 2 stroke. took the bost out last weekend.
I got about a mile from boat ramp and lost power. put it in neutral and sat for a sec then took back off. motor stumbled and struggled never would get back on plane or reach hi rpm. went home got new fuel pump and checked all hoses and fuel filter took boat back out no change. took it out again lastnight. tried activating choke while riding as per recomendations
by local boat repair shop, no change. stretched fuel line out on back deck with bulb in my hand and took off again. bulb is not collapsing and when i tried squeezing it no change in engine rpm. supposed to take my wife to Guntersvile for our anniversary this weekend and no shop can touch my boat for 2-3 weeks...somebody help me out here !

 

[99yam40]

1st thing i would do would be pull the plugs and inspect them.
next would be compression check all cylinders.
then check spark to all plugs

 

[bassfam334]

i did all of the above also.(except compression check) pulled all 3 plugs, checked gaps and noticed all 3 were wet. shined light into cylinders and all 3 were wet also. tried timing light just to see if they were firing but the light was acting up. got new light will check for spark tonight. motor idles ok with occasional random stumble.

 

[bassfam334]

did compression check lastnight.
cyl 1 was 122
cyl 2 122
cyl 3 120
used timing light to verify spark as i was by myself and had spark on all 3 cylinders. the only thing left i believe is to tear into the carbs. what are my chances of just being able to tear them down and clean them without needing kits ?

 

[99yam40]

very good chance it will not need kits as the gaskets are oring type.

is this an oil injected motor or premix?
is it remote or tiller?
posting a modle # helps others know what motor you have.

does the alarm system work?
overheat and maybe low oil will send the motor into a RPM limit and sound an alarm

 

[robert graham]

How old is the fuel in your boat's tank?....old gas can run bad...

 

[bassfam334]

it's a 40TLRC, Oil injected, remote steer. gas never gets more than a week or 2 old in my boat and i actually put new gas in it the day it broke. As far as i know the low oil alarm does work.

 

[bassfam334]

i didn't realize i never said it was a yamaha

 

[99yam40]

drain the oil tank to test low oil.
ground the pink wire at thermoswitch to check overheat

 

[bassfam334]

ok, low oil buzzer works but i don't know where the thermoswitch is and the only pink wire i can find splices off of 2 or 3 connectors and terminates in an unused female 4 pin connector that lays under the carbs.

 

[99yam40]

if it is like my 99 40 it will be on the cylinder head

 

[bassfam334]

ok yeah, i believe i found it thanks. i went ahead with my plans to pull carbs and check/ clean them today. carb #3 ( bottom) was the only 1 i found dirty at all. the emulsion tube under the hi speed jet had a cpl of the tiny holes plugged up. its all back together and i'm headed to get more oil so i can run it and see if its fixed.

 

[99yam40]

good idea to test the over heat alarm too, just to make sure it sounds the buzzer.

make sure you follow the link and sync procedure in service manual every time you put the carbs back on

 

[bassfam334]

well, i got back together saturday afternoin. i dont have a service manual for it yet. i didn't get to take it out til sunday evening but it ran awesome ! better than it's run in a long time. i plan to get a manual for it soon and i need to get 1 bowl gasket because the one on the middle carb leaks just a lil bit. i really appreciate all the help 99yam40. Thanks man !

 

[99yam40]

Good to here it runs well.
leaking fuel can cause bad things to happen and there is not much distance you can put between you and a burring motor out on the water

might want to check the float setting also, just in case there should not be a fuel level as high as the gasket/seal in the fuel bowl

 

[bassfam334]

im sure the level isn't supposed to be that high. it only seeps a lil when i leave the motor tilted. i placed an order this mornig for my manual and new bowl gaskets. 1 for the leak and a few spares as i'm sure this won't be the last time i have to get into the carbs.