[Harker]

I just rebuilt the carb and fuel pump on my 97 mariner 25hp #OG 490-408, manual start tiller. When I put the pump back together as shown in the Clymer manual with a gasket/pump body/gasket/diaphram...fuel came out of the outside gasket when I pumped the bulb. I took that gasket off and put it back together and it sealed up. Today when I ran it, it started right up but would die in a minute or two unless I pumped the bulb. When it dies, I can hear fuel entering the pump when I squeeze the bulb and the bulb gets hard. Does the outside gasket thickness make that much difference?Do I have the inside and outside gaskets reversed? Another piece of diaphram material came with the kit along with other stuff that weren't shown in the manual..is it the wrong kit? The boat ran like a banshee as long as I pumped the bulb. Thanks for any insight.

[Trent]

You got the gaskets in the correct place?? Number 17 installed correct way??

[Harker]

Thanks...this diagram is different than my Clymer manual..mine shows another gasket that goes between the pump body and the diaphram..but it wouldn't work because of passageways not being covered by the outside cover. My kit came with two gaskets..one like #17 and another that had an octagonal opening at the top..I'll take it apart again and see whats what..Thanks again.

[Harker]

Found the problem. The gasket between carb and powerhead didn't have the hole for the pulse lined up..made a hole and it works great now. I never noticed it when putting it on and taking it off 6 or 7 times...heh heh heh

[Gpsdependent]

Good catch....I had the exact same problem only it is on a 1999 Mercury 25 hp. The gasket kit from mercury had only one small hole on the intake gasket that lined up perfectly on the carburator side ....only problem is the gasket need a elongated hole because the "pulse hole" on the intake and the carburator do not line up exactly. Didn't notice it until reading this thread.. Thanks for the help, sure saved me alot of time and hair pulling.

[JDHNWFL]

I DONT BELIEVE IT!!!!!!!!!!!!!!!!!!!!!!!!!!
I almost added my motor to my reef!!!!!!
Had to add longated hole to carb gasket. Quicksilver is getting a nasty E-Mail!!!!

THANKS!!!!!!!