1987 115 dying under load

[rfiglia]

I have a 1987 Yamaha 115hp. Picked it up last sept. its on a 73 19ft Boston Whaler Outrage, very low hours, boat was always trailered. It ran flawlessly from oct till dec, I winterized it ran stabil through the carbs the who nine yards. Was using a portable tank last season cause the tank in the hull was bad. Over the winter I replaced the Fuel tank all fuel lines, fuel water separator the engine filter everything is new. The engine starts right up, idles fine, revs up at idle fine, once in gear is goes at very low rpm, as soon as I put it under load it dies. I ran it off a portable 6 gallon and it has the same symptoms, any ideas? Thanks so much...Rich

 

[rfiglia]

Re: 1987 115 dying under load

anybody?

 

[rodbolt]

Re: 1987 115 dying under load

test spark
test compression.
rebuild the carbs and replace the fuel pump.

 

[rfiglia]

Re: 1987 115 dying under load

ok spark is good, compression is good,will rebuild carbs and give it a try.. Thanks...

 

[rodbolt]

Re: 1987 115 dying under load

dont forget the fuel pumps wear out,go bad and can cause a crankshaft bearing failure.

 

[halas]

Re: 1987 115 dying under load

http://cgi.ebay.com/ebaymotors/ws/e...0403758740&viewitem=&sspagename=STRK:MEWAX:IT
There is one on ebay that should fit that motor

 

[daraghcummins]

Re: 1987 115 dying under load

Sounds like water in your fuel take a sample in a clear glass. Let it set and you will see a clear devide of fuel and water. Common problem solved by filling your tanks over winter so condensation cannot build up inside and turn to water. I have the same engine had this problem last year and thats what is was.

Use your second tank with fresh fuel no last years. Dismantle your carbs clean them and put them back on. Take your time doing it in particular take care with the pins. Almost certain its old fuel in the carbs that has turned jelly like and when you apply power she cant get enough fuel causing your problem. Hope it works will only take you an hour or so. How to do it is in the service manual few videos on youtube also. Try not to ajust the air and fuel mixtures if it was running well last year.

Hope it works out and if not at least you no that your carbs are clean. Wouldnt imagine its electrical.

 

[rfiglia]

Re: 1987 115 dying under load

rebuilt carbs today, mid range jets were clogged, she runs like new again.. Thanks for the replies.