On the lake - sputtering - anything to try?

NHGuy

NHGuy

Captain
Joined
May 21, 2009
Messages
3,631
Re: On the lake - sputtering - anything to try?

Does the shop manual offer any tests or troubleshooters for rough running or cutting out?
If it is electrical here are some ideas.
How are the wires from the dash, to ignition and controls? You could need something in there. How about the ignition switch? You could test that by doing continuity tests while whacking the dashboard with your hand. It's not the same as running at speed but it could approximate the banging a boat gets.
I only bring this up because I did some wiring on my 88 this year and that wire was pretty brittle and old.

Clean up grounds where you find them too.
Hope you find your issue, when you do please let us know.
 
S

smarks

Petty Officer 2nd Class
Joined
Mar 23, 2010
Messages
119
Re: On the lake - sputtering - anything to try?

Please let us know what you find. It does sound fuel related but check the ignition switch for loose wires just to be on the safe side.
Steve
 
superbenk

superbenk

Commander
Joined
Oct 27, 2008
Messages
2,033
Re: On the lake - sputtering - anything to try?

Ordered a new fuel pump, water separator & got some Sea Foam for the gas that's in there now. Hopefully all this stuff will finally make the thing run right! Not much left to replace :)

I took the old fuel pump off today & noticed there was a bit of gunk up the vent tube. It wasn't fluid like fresh gas, it was more like molasses. When I took the pump apart I noticed there was a bunch of this stuff under the diaphragm. It smells strongly of gas, but it's very thick & sticky... varnish?? Seemed like a lot of it. Or maybe a mixture of engine oil & gas?

Here's a picture of it seeping out that I took:

IMG_0420.JPG


I'm actually hoping this is a sign of the fuel pump being bad so that the new one fixes my problem. I'm wondering if I should rebuild my old pump and sell it on eBay? Is it worth the cost of a rebuild kit? Should I just sell it as is and not bother rebuilding it?

For those who are curious, I took a few more pics of the pump all apart (sorry for the quality - they're all taken with my cell phone):

http://picasaweb.google.com/superbenk/FuelPump
 
S

smarks

Petty Officer 2nd Class
Joined
Mar 23, 2010
Messages
119
Re: On the lake - sputtering - anything to try?

I've never rebuilt that kind of fuel pump before or even though about rebuilding one... but I would think after looking at your pics that a little bit of oil coming out from under the diafram would be normal.

After all the mech arm on the thing is in an oil bath. My boat has the newer style but operates the same way with the arm riding on a cam providing the pumping action but one side of the diapram exposed to engine oil.
Steve
 
superbenk

superbenk

Commander
Joined
Oct 27, 2008
Messages
2,033
Re: On the lake - sputtering - anything to try?

Installed new pump & water separator. Engine fired right up and ran great in the driveway. Hard to tell if the problem persists since it seemed to depend on 1) load & 2) high RPMs. I didn't run the engine over 2-3k RPM in the driveway. Ran it for a little bit at 2k RPM and it didn't cough or bog at all, but again, it's hard to tell if that means anything.

Hoping to be able to test the fixes on the water before vacationing on a lake for a week over July 4th. Last year we hauled the boat all the way up to the lake (Canandaigua Lake in NY) 6.5 hrs away where we rent a cottage ON THE WATER and it never ran well enough to really use it :mad:
 
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