Surging at WOT.....

evinrude40HP said:

I have a 1985 Mercruiser 140hp. I just recentley had a $600 tune up on the engine, which included spark plugs, wires, cap, rotor and a couple of other misc stuff. The engine starts up fine. As soon as I try to get up to 4200rpm it starts to surg and hesitate. I keep it under 2000rpm it runs fine. I need help. Thank you.

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Bond-o said:

Ayuh,... My guess is ya got Bad gas, or water in yer fuel...

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NHGuy said:

No but if you want to be proactive you can pump the fuel out through a filter, maybe filter it a couple of times if the gas is really loaded with stuff. You really do need clean gas to get good behavior.
If you can get the tank empty remove the sending unit and do a visual check inside there.
Also since your filters were that bad you'd also b smart to check the anti siphon valve for debris. It's right at the tank outlet.

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NHGuy said:

No but if you want to be proactive you can pump the fuel out through a filter, maybe filter it a couple of times if the gas is really loaded with stuff. You really do need clean gas to get good behavior.
If you can get the tank empty remove the sending unit and do a visual check inside there.
Also since your filters were that bad you'd also b smart to check the anti siphon valve for debris. It's right at the tank outlet.

Click to expand...