2003 yamaha 40 problem

[rhouston36]

my grandfather has a g3 with 2003 yamaha 40 two stroke on it. The past few years its only been ran a handful of times. So a few weeks ago i cranked it up and idled around for a bit and the overheat buzzer came on. After pulling it out of the water found out the water pump had started to come apart. Brought it to the house and replaced it and hooked it up to the hose and now the only way it will crank is by turning the emergency fuel enrichment switch to the open position. So far ive put in new spark plugs and fuel filter. Took the carbs off and cleaned them and pulled all the fuel lines off and checked them. all this and it still wont crank without the fuel enrichment switch on open. If anybodys got an idea of what i should look at next or something ive overlooked id appreciate it.

 

[wrechin2]

That doesn't sound good........ If it was running then overheated then now it won't run, It sounds like it damaged a cylinder from the overheat. If you understand how a 2 stroke works, then you know the piston also create a vacumme and draws air/fuel in. If ithas a damaged cylinder, then it will not have a stong vacumme and will not draw in fuel. By youadding fuel with the enrichener, you are inducing the fuel that the piston can not draw in on it's own<font color="#ff0033" size="6">BUT</font>other things need to ne checked out like the ignition needs to be verified (that all have spark) and a compression AND leak down test performed to see if it is or isn'ta mechanical issue. It may be a simple fuel quality issue. But the scenario you give, doesn't look good. I have built many engines because of damage from a impeller failing. None were at a idle though. Just my .02

 

[Booger]

wrechin2 - 7/1/2010 1:20 AM
and a compression AND leak down test performed to see if it is or isn't a mechanical issue.

Trust this man when he says it needs a leak down test. It will save you alot of trouble.

 

[wrechin2]

Booger - 7/1/2010 6:05 AM

wrechin2 - 7/1/2010 1:20 AM and a compression AND leak down test performed to see if it is or isn'ta mechanical issue.

Trust this man when he says it needs a leak down test. It will save you alot of trouble.

</p>

First hand experience. </p>

</p>

 

[rhouston36]

Ya that's what i was afraid of ill probably be givin you a call wrechin to see if we can set somethin up

 

[wrechin2]

Sure thing.

 

[Booger]

rhouston36 - 7/1/2010 9:55 AM

Ya that's what i was afraid of ill probably be givin you a call wrechin to see if we can set somethin up

you wont' be dissapointed if you take it to him. Hopefully you will get a better report than what I got though.

 

[wrechin2]

Booger - 7/1/2010 6:09 PM

rhouston36 - 7/1/2010 9:55 AM Ya that's what i was afraid of ill probably be givin you a call wrechin to see if we can set somethin up

you wont' be dissapointed if you take it to him. Hopefully you will get a better report than what I got though.

</p>

Do you care if I post a pic of yours?? Just to show how bad yours was and that itshowed good compression???</p>

 

[Booger]

Do I have to look emoBadLanguage just kidding. Please do, it may help others to understand the importance of the testing that you do.

 

[racinwithrex]

Nothing worse than having to ride home with a person who thought they had a good engine only to have found through a leakdown test that something was wrong. Well maybe the one having to drive home knowing that he is gonna have to pay for the lesson. It was a LONG ride home. But hey we'll be back at-im before long...........

 

[wrechin2]

I will post it tonight under your thread.