Have a 96 150/mariner EFI that intermittently acys like its running out of gas. Changed fuel lines and fuel filters and it did not help.

Carried it to shop and no luck finding out the problem. He said he thinks computer is bad. $1500 for a new computer.

That is a lot of money especially for just a hunch. Any ideas would be greatly appreciated.

A guy in my bass club had a 97 175 efi that would bog down when he opened it up. It would idle fine, but when he opened it up, it would intermittently sputter. Sometimes it would work beautifully and other times not so much.

The fuel system and plugs were checked and it was found that he had a bad ecu (computer).

This is an issue with the 2.5 L mercs, unfortunately.

Without having more information, it is hard to say that the ecu is the cause of the problem though.

If I were you I'd ask him what led him to that conclusion. Unfortunately it's possible that he went through a process of elimination that went with everything checking out ok and ended with its probably the computer. There's probably not a way to really test the computer so it's eliminate all else then throw a computer at it and hope for the best. If it's not something you're wanting to troubleshoot yourself then I would probably get a second opinion from another mechanic.

First off, if it is the ECU, they are repairable at a much cheaper cost, you don't have to pay that ridiculous price. Here's a link to just one of many that repair them the prices vary between them. http://www.simonmotorsports.com/

I'm not that much on Mercs/Mariners, but one thing I would do that often gets over looked and I have seen cause problems a number of times in the anti-siphon check valve at the fuel tank. If it has not been removed, you might want to try removing it and see how it does. There is a 3/8 barbed fitting at the fuel tank the fuel line to the engine is connected to. Take that fitting out and see if there is a check ball inside. If there is, get a regular barbed fitting and replace it the check balled one with a standard fitting. This fitting is a coast guard requirement so that if the engine catches fire and going up in a blaze of glory, when the fuel line burns off in the motor, it's to keep the burning fuel from being pulled back into the tank, but has caused many problems with sticking and not letting the fuel to the engine. Check it with a standard barb, if that fixes the problem, they you can either leave the standard one, or buy another anti-siphon one. I take mine out and throw them in the trash.

The real Merc/Mariner gurus are on Scream and Fly if you want to try there. http://www.screamandfly.com/forumdisplay.php?20-Technical-Discussion, but there may be someone on here with experience on your motor/problem.

Thanks I will try antisiphon valves first.

After further inspection I noticed the ends of the yellow and red wires on the CDI voltage regulators look burnt.

Could this cause the same type of problem where it seems to drop cylinders?