1978 SeaRay Mercruiser 228 stalls at high RPMs

"I have a 1978 Mercruiser that

"I have a 1978 Mercruiser that was in storage for quite some time. Engine was rebuilt and run only a few times before being stored. I drained all the old fuel, flushed and dried fuel tank, replaced fuel pump, replaced check valve at tank, had Rochester Quadrajet rebuilt, replaced coil, plugs, points, condensor, cap, rotor and wires. The problem I am having is that when I put the boat in the water, it runs fine until I throttle up. After about five minutes, it just stalls and I have to let it set for a good ten minutes before it will start again and then it will only run up to about 1000 RPMs. It feels like it is starving for fuel but there is still fuel in the carb. Any suggestions?"

"You cleaned the filter in the

"You cleaned the filter in the fitting that enters the carb?

You cleaned the filter in the fuel pump?

You checked the pressure the fuel pump gives 4-7 psi ?

Vent clear?

All the wires on the plugs right none crossed?

Timed right?

Ok run the boat after you check the above on a external tank of gas you might have to clean the carb again, before you run it on the external tank of gas let us know how it ran."

"I replaced all filters in the

"I replaced all filters in the fuel system, replaced the fuel pump, fuel pressure is good, fuel tank vent is clear,timing is set to specs on tag on valve cover, I did not check advance at hi RPMs.I have run it on fuel in tank and an external tank last season and get the same results. When the carb was rebuilt, it was done with a standard kit from an auto parts store, I have been told that I should have used a special kit made for marine application. I have been considering changing to a Holly carb just beause of my experience with the Chevy V8s that I ran in my cars years ago. I have also been told that the exhaust baffles could be part of the problem. Thanks in advance for any help.
Frank"

"Pull the cap, pull the point

"Pull the cap, pull the point plate off and check the mechanical advance to see if it is frozen."

Did that last season. Took it

Did that last season. Took it out and made sure it was all free and lubed everything.

"The fact that it runs (an

"The fact that it runs (and you did not specify if it ran at full speed??????) assuming it did,

What is your motor temp? If it is getting to hot that would do it.

Should be 180 or less at full speed. If it is climbing to 200 or so you have a problem.

how about some more info/details on the max rpms before this occurs and the temp. Have you checked for spark immediatly after this happens? You say you have gas so there is only 3 things to look for.

Ignition
compression
fuel

when this issue occurs you need to identify which one is missing."

I probably won't be able t

I probably won't be able to get it out on the water for another month ( it's still winter here in northern Michigan)I will go through everythimg then and see what I find. Thanks for the help for now.
Frank

"You may wanna check the plugs

"You may wanna check the plugs and see if they are "normal" or not. A vacuum gauge would be helpful, too."

"Do the vacuum check. You post

"Do the vacuum check. You posted that the motor was rebuilt, you check the compression ?

Valves too tight ? Guy who did the motor couldn't figure out why it was doing what it was doing to you, last thing a guy checks is the valves he thinks he set them right when he didn't. Just conjecture on my part, but that could be why."