Fuel Filter??

[dmiles452]

This past weekend my 1989 Mercruser 5.7 would not come up on plane due to only reaching 2200 rpm at WOT. I am thinking fuel filter. Any other suggestions?

 

[Chris1956]

Those older carb models had a small cylinder-shaped paper filter in the fuel connection to the carb, plus a porous filter stone on top of the mechanical fuel pump. Did you replace those?

Antisiphon valve is another likely candidate.

Also, on my'88 SeaRay, the fuel tank pickup had a filter inside it. It was partially clogged. One needed to pull it out of the fuel tank and unscrew the outer tube to get to it to clean it.

 

[Faztbullet]

Which carb ya got? Mercruser,Rochester,Weber? Mercruiser does not use a stone filter as it has the screw on WS filter for this model.

 

[airshot]

Go thru the entire fuel system from tank pickup, fuel lines, water seperator, and filters.....fuel lines degrade from the inside, hopefully your filters catch it all.

 

[QBhoy]

Hi. Out with being a fuel issue…it could be a result of other things that are making the boat struggle to plane. Like propeller damage, outboard trim position not fully down, Hull growth…engine health or additional weight in the rear of the boat. I’d expect if it is one of these things, then that’s about all the rpms you would get if it isn’t planing.

 

[dmiles452]

This past weekend my 1989 Mercruser 5.7 would not come up on plane due to only reaching 2200 rpm at WOT. I am thinking fuel filter. Any other suggestions?

 

[dmiles452]

As it turns out, it is not a fuel issue but a distributor issue. I removed the cap and found the module had disintegrated. Now to figure out how to wire the new module to the existing engine harness.

 

[Chris1956]

Gee, I replaced the ign module in an '88 MerCruiser, and it was plug and play. The only issue was that I needed to pull the rotor shaft out of the distributor to replace the module, which meant pulling the distributor.

I had not done that kind of work since high school shop. It took me 2 tries to remember that the distributor can go in 180* out of time.

 

[dmiles452]

This past weekend my 1989 Mercruser 5.7 would not come up on plane due to only reaching 2200 rpm at WOT. I am thinking fuel filter. Any other suggestions?

So I changed the fuel filter and still had the same problem. So I checked out the distributor. Removed the cap and saw that the sensor had disintegrated. I replace the sensor, however the new one has three wires where the old one only had two threaded stud type connectors. One stud had two white/green wires connected to it and the other a white/red. So I put the two white/green together and connected to new white green and made the connection to the white/red. The motor starts but will not stay running. what am I missing?

 

[dmiles452]

So I changed the fuel filter and still had the same problem. So I checked out the distributor. Removed the cap and saw that the sensor had disintegrated. I replace the sensor, however the new one has three wires where the old one only had two threaded stud type connectors. One stud had two white/green wires connected to it and the other a white/red. So I put the two white/green together and connected to new white green and made the connection to the white/red. The motor starts but will not stay running. what am I missing?

Is there a fuel pump interlock on this system? Something that prevents fuel flow without a given signal?