1989 pro50 yamaha boggs down and dies at WOT after a few seconds

[catfish1981]

Hi Guys n gals. Im gaving a problem with my 89 yama pro50lg. It will idle fine but very cold natured. when I let it warm up, I can hole shoot and after about 10-20 seconds,it quickly boggs down and dies. afterwards, it is hard to crank. I have noticed, when it starts cutting out, and I pump the primer bulb, sometimes it wont cut out, or will go for a full few min. before cutting out again. By my specs, 130 on all cylenders, getting good spark, and the carbs are clean as a whistle (as I work at a marine shop as a boat mechanic :facepalm: ...lol) from my ecperience, Im thinking fuel pump...any other ideas? Thanks guys n gals!

 

[99yam40]

Re: 1989 pro50 yamaha boggs down and dies at WOT after a few seconds

checking fuel pressure /vacuum should indicate if and where problem is if there is one in the fuel delivery

 

[catfish1981]

Re: 1989 pro50 yamaha boggs down and dies at WOT after a few seconds

Yea didnt think about pulling vacuum on fuel line..thanks. will try that before my next catfishing tournament. Thanks! Maybe a pinnhole in fp diaphram

 

[99yam40]

Re: 1989 pro50 yamaha boggs down and dies at WOT after a few seconds

or a restriction in pick up line.
That is why measuring the vacuum pulled by pump along with the pressure it puts out are both good tests

I was not saying to pull a vacuum for a test, just measure what the pump was doing on inlet and outlet.

Also look for air being sucked into system
http://forums.iboats.com/engine-fre...ow-testing-your-boats-fuel-system-283363.html

May need to make sure carbs are clean and adjusted properly like manual calls for if it is cold natured.
Make sure timing is in spec also. My C40TLRX had a CDI problem that caused idle timing to be out of spec

Have seen it take multiply times to finally get them clean enough.
And always do the link and sync after reinstalling carbs, Every time they are reinstalled

 

[catfish1981]

Re: 1989 pro50 yamaha boggs down and dies at WOT after a few seconds

Man thats some great tests..I appreciate it.Will post results soon!

 

[erwinwahoo14]

Re: 1989 pro50 yamaha boggs down and dies at WOT after a few seconds

Man thats some great tests..I appreciate it.Will post results soon!

I`m really interested in your results. I have the same issue with my `90 pro50. I hope it will be something simple like a clogged air vent (mud wasps) or a weak fuel line that collapses under a heavy load. My next run I will have an auxiliary tank and fuel bulb to help isolate.