any suggestions

[creaux71]

i have a 1998 yamaha 30hp, it has 3 cylinders and 3 carbs, the engine appears to be running good, it cranks on the 2nd pull. the problem i am having is that i cant get it to leave out the hole, it is lugging down and takes forever to build speed and plain off. i went to the yamaha dealer and they suggested a new prop, so i put a ss prop with a recommended 13 pitch hoping to solve the problem, well its still there... the motor is on a 14ft allweld, so it should push the hell out it. i just cant get it to leave as strong as it shoul. any suggestions?

[99yam40]

Check compression and spark on all cylinders along with the timing and then clean the carbs

[creaux71]

can you tell me what the compression and timing should be if all is good, so i will know if its good or bad

[200090tlry]

Well im thinking different

98 motor humm im going new fuel pump diaphram kit and back gasket. If carbs are clean and adjusted correctly first before trying fuel pump and it still dogs a new prop might help out. That's assuming you have good fuel and oil in gas. And if you read previous posts online bulbs,orings in fuel system like quick connects. I went through same thing on 2 outboards and all came back FP. Havent had any spark issues or timming issues yet knock on wood. On 98 I would replace some fuel related parts not just FP. Also it costs nothing to check if fuel pump needs little tighten down. If it runs like raped goose after that you know the issue.

[99yam40]

I do not have a service manual for your motor but you need to get one if you plan on working on it.

It is best to test what you can before replacing parts

[creaux71]

i put a new fuel cell, new fuel line, new ss prop and new plugs! the engine is oil injected, the cap was cracked on the oil tank so i drained it and put new oil and a new cap, it was suggested that it may only be hitting on 2 cylinders. if so how could i tell for sure.

[creaux71]

can you be a lil more specific on tightening down the fuel pump? didnt quite follow all of what you were suggesting

[99yam40]

Check compression and spark on all cylinders along with the timing and then clean the carbs

Did you not understand what I said?

[creaux71]

99yam, if you look, i was responding to the other person who suggested i tighten up the fuel pump, which in turn is the reason for the question about the fuel pump, but thank you for your input, i will let you know if it was a timing or compression issue!

[99yam40]

it was suggested that it may only be hitting on 2 cylinders. if so how could i tell for sure.

This is what I was responding to.

If it has good compression on all cylinders and the timing is advancing properly, make sure you use a spark tester to check the spark on all Cylinders. A timing light will also help check the spark if moved to the different plug wires and tested while problem is happening.
Spaying some fuel mix into the different carbs while problem is happening will give some indication if there is a fuel starvation problem.