1989 yamaha 175 hp hesitates

[nickantanies]

hello, I just purchased a (supposably) rebuilt motor this past season. After having too many problems with my mercury 150.. Anyway the boat this motor is on, is a 1989 19ft arrowglass centerconsole (fiberglass).My top speed at WOT is about 40 mph on a good day, with the rpm's at about 5700-5800 with a 16pitch prop. Does that sound right to anyone? For some reason i'm thinking somthing is wrong, becasue with the merc i was running a 19 pitch prop at WOT i was doing about 45mph at 5800-6000 rpm's.. Can anyone help in giving me idea's on what i should do first. I spent a ton of money on the old motor and a bunch on this new one, so i'm all out!! I need to narrow it down so i don't get shammed again... could it be compression? Ok problem #2 is the tube in the gas tank broke off and I had a new one made! since then the boat has not been running right it hesitates everytime i give it gas, and acts like its gonna stall. It starts up fine and has never given me any other trouble. I'm thinking the end of the gas pick up might be too close to the bottom of the tank. Does anyone know how much space there should be from the bottom of the tank to the top of the fuel pickup?<br />thank you appreciate any help

 

[Ray Neudecker]

Re: 1989 yamaha 175 hp hesitates

It certainly sounds like fuel starvation. Testing with a seperate small tank will help to determine where the problem is. There may be a difference in the gear ratios also. Many of the Merc 150's had a 2/1 gear ratio where your engine is 1.86/1. First thing is to find and fix the fuel problem or you will cook that motor.

 

[nickantanies]

Re: 1989 yamaha 175 hp hesitates

Thank you for the help, I will try using an external gas tank. Do you know how much space should be between the bottom of the gas tank and the feul pick up tube?<br />thanks again,<br />nick

 

[nickantanies]

Re: 1989 yamaha 175 hp hesitates

Another question? Do you think thats what could have fried the other motor??<br />thank you again<br />nick

 

[Ray Neudecker]

Re: 1989 yamaha 175 hp hesitates

An excellent chance that it did and will do the same to this one. Fuel starvation is a number one cause of blown powerheads. They make aftermarket pickup tubes. I would cut it about 1/2 inch from the bottom of the tank. If you have not removed the anti siphon valve from the tank fitting, then I would do so now. Testing with an external small tank will help to trouble shoot the problem.

 

[nickantanies]

Re: 1989 yamaha 175 hp hesitates

I had to get mine fixed by a welder. I could not find anyone wwho sold that peice aftermarket. Do you know of anywhere I can order it? Thank you again for the Help it is greatly appreciated.<br />Nick

 

[Ray Neudecker]

Re: 1989 yamaha 175 hp hesitates

It is available through most marine parts distributors. Almost any marine dealer should be able to order it for you.