1998 VMAX 200 fuel pump diaphram issues

[evinrude20]

My brother in law has owned his boat for about 5 years now. Its got a 98 vmax 200 with maybe 200 hrs on it. Idles, runs great. Most of the time. He has had to replace the fuel pump diaphrams 3 times now. This previous time it happened on day 1 of a bass tourny we were fishing. You can tell it will happen because it starts alot harder and you can smell the gas. And then they finally give and you cant run anymore. I ended up pumping the bulb for 1.5 hrs so we could limp back to weigh in at about 10mph. (also burned a crapload more gas!) im wondering if this is a bad batch of
Diaphrams, or if anyone has any other ideas? He only uses 91 an yamalube oil. The dealer who did the first 2 fixes said they replaced them on a motor once in a 3 year period. Something seems fishy. As i dont like to quit, we spent most of the night and built 2 diaphrams out of vinyl innertube patch(since its durable and flexible) and test ran it. Ended up giving us the whole day 2 on the water with no issues at all. Appreciate any comments!
Thanks

 

[99yam40]

Re: 1998 VMAX 200 fuel pump diaphram issues

I would not think that material is safe for contact with fuel.

I would stick with the Yamaha parts.

Running with one or more of the pumps leaking can wash the oil off cylinder walls and pistons and cause major damage

some motors are hard on the pumps and need to be replaced every few years under normal running, but if it lean sneezes it can take it out very quickly.

I would change pumps as Yamaha dealer recommends and carry a spare complete pump just in case

 

[evinrude20]

Re: 1998 VMAX 200 fuel pump diaphram issues

If I had access to the yamaha parts we would har used them. This was a last resort for 1 day only. How would one fix the "lean sneeze"? Where the hole is they look like they have been burned, like when burn plastic. He just bought 6 of them from this site (8$ vs 33$ at rhe dealer) and will be keeping a 10mm socket and phillips on hand. But it would be nice to not have to do this so often.

 

[99yam40]

Re: 1998 VMAX 200 fuel pump diaphram issues

Question is does it have a lean sneeze at idle or off idle?

if it does then clean and adjust carbs