WOT problem/ fuel system issues: 40 hp mercury, 2 stroke, 4 cyl- 1990's

neamakri

Cadet
Joined
Aug 7, 2011
Messages
14
I have a 40 hp mercury, 2 stroke, 4 cyl- 1990's. will idle fine, run in the driveway ok. At plane/ wot - it dies. IT started 4 trips ago. 1st trip would go to WOT, but got on plane, second trip, got on plane in the am, would not plane later, last trip , would not plane.

I have checkd the following:

1. fuel - it s new
2. fuel lines- replace some, not leaks
3. fuel filter (in line) - clean
4. water sperator- ok, v. clean
5. tank- new

have not checked
1. compression
2. fuel pump

its a 1990's 2 stroke, 4 cyl. ( dont know exact year)

thanks for the help.
 

pootnic

Chief Petty Officer
Joined
Aug 11, 2007
Messages
447
Re: WOT problem/ fuel system issues: 40 hp mercury, 2 stroke, 4 cyl- 1990's

Anyone...
It still may be a fuel issue.
Try pulling the choke see if that helps a bit,if not try sqeezing the fuel ball,see if that helps.
Your fuel tank has a vent,is it working?
Simple stuff first....
Compression check wouldn't hurt,could have to rebuild fuel pump or have carbs cleaned also.
Whats it doing,when won't plane...does it try to pick up rpm?
 

neamakri

Cadet
Joined
Aug 7, 2011
Messages
14
Re: WOT problem/ fuel system issues: 40 hp mercury, 2 stroke, 4 cyl- 1990's

got a new / old pair of WMA carbs of ebay, cleaned them up , rebuilt fuel pump, changed all fuel lines to ethonal standards ( thanks Obama) and it runs great in the driveway.
I have the screw set to 1 1/2 turns out, now its time for the river . any sugeestions on adjustments ?
 
Top