On my 60 2 stroke, it seems that the fuel pump is going bad again. While running at the upper rpm range, the motor has cut out once in the past two trips. Power drops to a semi rough idle, turn motor off then she cranks up and runs fine. I had the same issue this spring and replaced the following, new anti-siphon valve, new fuel lines, new primer bulb and filters (changed/cleaned every 3-4 months). I even ran the boat with a portable fuel tank to eliminate the existing fuel tank as a culprit (as per my local yamaha dealer), had the same loss of power. At that point, the dealer said it was most likely the fuel pump, replaced it (yamaha oem part) and had not had an issue with motor since this past spring. Is it something else besides the fuel pump, again? Motor runs fine, otherwise.
Pull the 2 bolts that hold the fuel pump to the block, only those 2 (leave all the other lines hooked up and screws alone) With the 2 bolts out prime your primer bulb and see if gas squirts out of the back of the fuel pump. There is a little hole in the back of the pump gas should not come out of it. If it does then R&R the fuel pump and go fishing, if it doesn't then you have a different problem. Let me know Standing by
Exactly what Creek runner said, but let me add a small amount more... On the fuel pump, theres a small tip of the diaphram that sticks out on top. Is it white or black? White is bad in this case. Also, you said you replaced the primer bulb. Did you use an oem yamaha, mercury etc brand or attwood, moeller? Aftermarket bulbs suck
guys, I took the 2 bolts off and no gas leaked out when I squeezed the primer bulb. Now what? Also, I did not see any part of the diaphragm that sticks out on top, but there are two white tabs on the sides of the fuel pump.
Yours stick out the side because your pump is mounted sideways. The white tabs could indicate a problem with the diaphragm, Yamaha switched from the plastic white diaphragms to black rubber style due to issues with the white ones; but I have never seen a fuel pump with the white tabs that didn't test bad (You tested yours with my previous post) and was intermitting. Which your issue seems to be. 1st) Pull a fuel sample disconnect the primer bulb from the engine side and pump some fuel into a clear glass jar. Check and make sure there is no water or thrash. 2nd) When you replaced the primer bulb did you use a Yamaha one or after market. If after market switch to an OEM one, I like Mercury's best but any OEM will do. 3rd) The next step would be to run the boat on a portable tank with different fuel line and primer bulb. This will tell you if you have a boat problem or motor issue. 4th) ) R&R the fuel pump, Intermitting problems are always the hardest to diag!
my local yamaha dealer had not heard of any issues with the white tab diaphragm, all they had were the white ones and did not know about the black one. How do I get a black one? I had purchased a new one, prior to this post (white tabs) and installed that since the dealer had the same one's. BTW, installed new oem primer bulb this weekend. I'll update this weekend to see if the problem is fixed.
Lol they are a bit "out of the loop".. Yamaha upgraded to the black neoprene diagphram a couple years ago. They might just be trying to get rid of old stock Dont buy a white one
What am I missing? I went to another Yamaha dealer in a different county and was given the same pump with the white tabs. He said that he has never heard of an issue with the diaphragms being switched to black neoprene. He also said that he has sold over 17 this month and that he does not have old stock. He even crossed reference the last year of the 60 and 90 hp 2 stroke fuel pump to see if a different one was used, same pump. So, how do I get a black one?
I went back and pulled the bulletin and it did not affect your engine. Also like I said in my previous post, I have never had a fuel pump that was bad test good. You did the test I told you so it's probably not your fuel pump. Pull a fuel sample, check you filters, you already replaced the primer bulb. Has the engine acted up again?
Fuel was good, filters were changed and bulb was replaced with Yamaha bulb, hose, etc. I'll make a test run this weekend. I appreciate all the help
I experienced a similar problem on my '02 90 and did all the things you have done because I didn't want to clean carbs like G at CFM told me to do. I finally broke down and cleaned the carbs to find a bunch of crud in the float bowls. Haven't had a problem since.
I believe problem was either primer bulb or fitting at motor, replaced with OEM parts and runs like champ
