1996 Byliner 3.0l mercruiser stalling at higher rpms

Hi all, this is my first post! I purchased this boat about 5 years ago, the previous owner didn't take care of the boat at all. It only has 142 hours on the boat. The boat never ran good, I was always nervous when taking it out. I had someone winterize the boat for me every year till last year. When I winterized the boat, I mistakenly put anti-freeze in the intake plug. I know, stupid, right? When I started the boat this year, I had what I thought was water in the oil, so I brought the boat home with me and took it apart. The manifold was good, the Head was good so I replaced all the gaskets except the water pump and oil pan. I started the boat and ran it with ear muffs, it ran just like it did before, engine shaking, and had to pump the throttle to keep it running. I started playing with the timing, (no timing light yet) and the boat started running GREAT! It must have been off before i bought it. It starts right up and idles great, however when I start putting the rpms up, it wants to stall. I replaced the filter in the carb, The boat store didn't have the filter for the pump but said I could install an in-line filter before the pump, so I did. I've noticed the in-line filter only has gas about half way across the filter, should it be completely filled? Its installed horizontally, not vertically.

Any help would be greatly appreciated.

Re: 1996 Byliner 3.0l EFI mercruiser stalling at higher rpms

Re: 1996 Byliner 3.0l EFI mercruiser stalling at higher rpms

dwh351 said:

The boat store didn't have the filter for the pump but said I could install an in-line filter before the pump, so I did. I've noticed the in-line filter only has gas about half way across the filter, should it be completely filled? Its installed horizontally, not vertically.

Click to expand...

You shouldn't have a clear filter in the fuel system, fire hazard... They should have sold you a water separating fuel filter which will cure 2 problems, water in the fuel and also debris in the fuel. For the clear filter being 1/2 full, I bet the filter is on an angle or sitting horizontal, not an issue with it being 1/2 full in that orientation as the fuel can't push/pull the air bubble out.

You'll need to get a timing light and time the engine correctly, doing it by ear could cause serious problems if it gets advanced too far.

For the stalling upon acceleration, sounds like the accelerator pump is bad, time to rebuild the carb.

Re: 1996 Byliner 3.0l EFI mercruiser stalling at higher rpms

Re: 1996 Byliner 3.0l EFI mercruiser stalling at higher rpms

Thank you, I will purchase the water seperator/fuel filter, I will get a timing light from my dad's this weekend. As far as the carb goes, is it hard to rebuild?

Re: 1996 Byliner 3.0l EFI mercruiser stalling at higher rpms

Re: 1996 Byliner 3.0l EFI mercruiser stalling at higher rpms

okay, this is what I have done so far, I set the timing with a timing light, the way the manual shows and it is running good now!! I am going to remove the inline filter all together and replace the fuel hose and put a filter back in the pump.