merc 3.7 170 dies at WOT

Hi,
new to the forum, can anyone help me please?
My boat has been stored for a good 12 months. Got it out and ran her up. It ticks over fine throttles up ok, and runs fine at about 20 - 25mph.

Problem begins when I open up the throttle fully, after about 3 seconds engine seems to starve of fuel and proceed to die. I sometimes get a few back fires (running lean?) if I drop the throttle back down it runs fine again.

I have swapped the coil, condensor. So guesing fuel pump or carb. possible vanished?

I have disconnected the fuel line from the carb turned over and got fuel pulsing out.

The carb filter looks clean.

any ideas?

Does the 2bbl mercarb have both low and high needle jets?

Any advice much welcomed...



thanks
adam


Its a 2bbl mercarb.

Re: merc 3.7 170 dies at WOT

Could be several things in the fuel system before the fuel gets to the fuel pump.
Try the tests in the thread below.

http://forums.iboats.com/showthread.php?t=283269

Re: merc 3.7 170 dies at WOT

Thanks Don for you help.
I got it running in the end. Unfortunatly I can not be exact as to fix to the problem but this was my findings it may help others,

Removed carb expecting to fine the insides a mess. Inside spottless, even it had been standing for some time. While I was here rebuilt the carb anyhow. But really did not think this was the issue.

Removed fuel pump, but trashed the thread trying to gain access to the filter. So ordered new pump.

Fitted new pump, and then just as I was reattaching the sight tube I noticed it was completly blocked. The sight tube runs from pump to carb. (could this blocked tube cause the pump diaphram not pump enough fuel at WOT!) I will never know.

All back together now and she runs sweet!

I will be kicking myself if the sight tube was at fault.

thanks guys

Re: merc 3.7 170 dies at WOT

Sight tube is only useful when the pump takes a dump. That rhymes. It's purpose is to send the fuel back to the carb to avoid a nasty fuel dump situation.