How a motor could be affected by varnish in the gas tank?

[Barryyamaha]

I just purchased a second hand yamaha 4 hp boat motor.<br />Model Yamaha 4MSHS<br />Serial number: 6GE0 S 146428 , year 1994<br /><br />When I received it I found that gasoline was left in the tank and it turned to varnish. <br /><br />I have been told to use a cleaner to remove the varnish. But I would like to know how bad this problem is going to be for the motor in the future. Could that varnish have affected the motor forever even if I clean it?<br /><br />If I ask an specialist to make this job, is this work going to be expensive?<br /><br />Thanks a lot!<br />Barry

 

[Fouled Plug]

Re: How a motor could be affected by varnish in the gas tank?

Barry, varnish can gum up carburetor passages and needles/seats/floats. It isn't terribly difficult to clean the residue from the tank, and soaking the carb and blowing it out with compressed air will remove the crud. No permanent damage will be caused (unless you run an engine too lean due to a dirty carb) With a manual and some patience, it is not something you couldn't accomplish in your spare time. A 'pro' might ding you a couple hours labor + parts.