Will this boat ever run???

[danthern]

1977 omc stern drive 235 hp 351W. Idles great, at about 1500 rpms, it loses power in the yard and in the water. I have replaced the plugs, wires, cap, rotor, points, condensor, rebuilt the carb, checked the fuel system . The filter is clear. I put the fuel line in a bucket of gas to rule out a stopped up fuel system, no difference. Timing is set at 4 degrees BTDC, points are at .018. What else can it be? Bad distributor, fuel pump??? All advice would be greatly appreciated!<br />Dan

 

[kenimpzoom]

Re: Will this boat ever run???

What is the history of the motor?<br /><br />Did it all of a sudden have this problem, or did it start after storing it, etc...<br /><br />Sounds like fuel to me. Carb may have something not put together right.<br /><br />Ken

 

[danthern]

Re: Will this boat ever run???

Thanks for replying...The motor is one that I bought to do an engine swap. I was told that it was recently rebuilt and it looks like thats true, everything is newly painted, clean, etc. When I bought the boat, the block was busted so theres really nothing to compare to. I'm pretty certain that the carb was reassembled correctly. I'm at a loss....One thing that is different is the intake on the new motor. Its an edelbrock performance model. Think that would make any difference? I have the origional...do mechanical fuel pumps go bad often? I see no leaks, etc. Thanks for any thoughts.<br />Dan

 

[McKenzie]

Re: Will this boat ever run???

I'm not sure if its because of the year of the engine, but most of the carburated 351W's i know are set at 10 degrees BTDC. I know some fuel injected 351's are around 4 or 5 degrees BTDC. Do you have a fuel pressure gauge you could check your fuel pump with? In regards to the intake manifold, it will work. But if it is aluminum, it won't hold up in a marine environment. Heres a post from a few weeks ago that explains it. Click Here What year is the rebuilt engine you put in?

 

[akriverrat]

Re: Will this boat ever run???

might be valves set too tight. fuel delivery problems usually don't happen same rpm with and without a load on the motor.

 

[kenimpzoom]

Re: Will this boat ever run???

Was the engine running before in another vehicle? Or is this the first time it has run?<br /><br />Some more ideas:<br /><br />Fuel pumps can go bad, a fuel pressure gauge will tell you quickly.<br /><br />Did you check the dwell, maybe the points cam is worn.<br /><br />Did you check the vacuum, it can tell you the condition of the valves.<br /><br />Did you run a compression test?<br /><br />Are you sure the plug wires are in the right place?<br /><br />Is the coil new?<br /><br />Ken

 

[scootiebird]

Re: Will this boat ever run???

Take a look down the carb (without the engine running and actuate the throttle. You should see a stream of gas in each barrel of the carb. If you don't, this is an accelerator pump not working. 1500 rpm is right about where most engines need this extra squirt of raw gas to start running faster and faster. This is very common on engines that have not been user for a year or more.

 

[bubbakat]

Re: Will this boat ever run???

make sure the valves aren't set to tight

 

[danthern]

Re: Will this boat ever run???

Thanks for all the excellent suggestions....to answer some questions....I have also seen where some folks set the timing @ 10 BTDC...I'll try that. The motor is a 1977 model identical to the one i replaced, and it was running in the other boat. I'm positive of the plug wire placement, I haven't performed a compression check nor a fuel pump check. The coil is new, the accel. pump is functioning. Carb was rebuilt 2 days ago. I will get a check on the compression and the fuel pump and go from there. Thanks to everyone, you guys are great! I'll keep you posted.<br />Dan

 

[danthern]

Re: Will this boat ever run???

By the way, I took the following marine parts off the old motor and put on the new one...carb, distributer, water pump, harmonic balancer, alternator