1990 yamaha 175 hp idel and bogging problem

[clevecan]

Hi all, I bought a 1991 Kingfisher with a Yamaha 175 that has been sitting for years in there garage. the boat and motor looks new. He said he only ran it 3 or 5 times sence new off showroom. I could tell when he cranked it on water hose it was running a little rough but he had been out there trying to have it running for me for when I got there to look at it.
starts fine but I ask him when was the last time he added fresh gas he said 5 to 7 years ago I think 10 being thats the last sticker was put on it 2003. He is a old guy . I seen him as I got there trying to get in running and he was useing the warm up lever telling me that was the choke and he said the togle under key was just to spray a splash of gas. I ask him if he pump the gas bulb he said theres not one.well there is one so I walked around with him not seein me and pumped it up and pulled the choke at the motor and then it fired up fast LOL.. So I now have got all old gas drained from tank and put new gas and cleaned carbs and then backed it down the boat ramp and it starts fine but boggs and won't idel in water. it runs on hose but once in the water of cource it dont. I'm thinking the Plugs now once I think back being he probly gass fouled them? HELP!

 

[99yam40]

Re: 1990 yamaha 175 hp idel and bogging problem

What no compression tests?Spark tests? timing or fuel pressure?
Seems like a motor that sat that long may have some rust problems on all sorts of internal shiny parts

 

[clevecan]

Re: 1990 yamaha 175 hp idel and bogging problem

Well yes compression was great all 6 cly, spark test 7/16 great, He winterized it yearly thats why I was saying the plugs are probly done!
He used what yamaha gave him and sprayed in all cyl's yearly. theres only 20 or so hours on the motor sence new I asure ya. It looks like it just came out of the box.

 

[clevecan]

Re: 1990 yamaha 175 hp idel and bogging problem

I rebuild all carbs they were all very clean, never found what the floats level setting was. They all were ajusted with looking at carb body upside down almost level with body but slitely higher on free end.

 

[99yam40]

Re: 1990 yamaha 175 hp idel and bogging problem

Saying compression was great means nothing to me and maybe others also.
Give us some accurate numbers.

23 year old fuel pumps and water pump I would not trust to function properly

timing is easy to check

If compression ,spark, and timing are all good then you are left with a fuel to air ratio problem.
Too much or too little fuel will not let cylinder fire properly
backing it into the water causes more back pressure on exhaust,
and maybe it is running too lean to run up under the extra load

Pick up the Yamaha service manual for this motor and make sure you follow the procedures in it for link and sync and adjusting the carbs every time you reinstall them back onto the motor

If he only sprayed in the cylinders and did not spray the fogging oil into the intake, it would not protect the crank and bearings

 

[clevecan]

Re: 1990 yamaha 175 hp idel and bogging problem

I understand thanks for the info, I will order a service manual today .