75 horse Chrysler Starting Procedure/help

[bashr52]

I have a 1980 75 horse Chrysler on my new boat, and the only pages missing from my engine manual are those on the starting procedures, go figure! I just bought this boat last week, replaced the bad starter, cleaned all battery cable connections, fresh gas, new plugs, etc.

I pumped the primer bulb up until there was pressure, set the throttle to neutral warm up, and cranked it over with the chokes closed. It will fire and run for about 1/2 a second, or so occasionally. usually, once the engine fires once, it kicks the starter drive off the flywheel and stops, while the starter just turns in place. It will not stay up if it fires. I can't keep it engaged long enough to allow a good start/restart. Suggestions? Is this the correct starting procedure?

Also, after I pump up the prime and crank it and it fires a few times, the primer bulb is soft again. I tried cranking the engine over without the outlet line to the carbs connected to the fuel pump, and nothing comes out. All the gaskets and such have been replaced in the pump, screen is clear, and if you remove it and apply a vacuum to the vacuum line it pumps fine. Should it be pumping when the engine is spinning off the starter?

Thanks!

 

[moparman]

Re: 75 horse Chrysler Starting Procedure/help

If this is a new motor to you ,and you don't have any history on the service that's been done to it , start with the main service items, water pump impeller, fuel pump diaphragm[which sounds like your issue]and check valves, and lower foot oil change. By doing these things ,you know when they were replaced last and can do your future service based on this history of replacement. These items need to be replaced every 2-3 years as a p/m [preventive maintenance] to keep you running on the water ,not broke down ,getting towed in . Keep us posted on your progress and look at your fuel system [pump and check valves]. Hope this helps

 

[john from md]

Re: 75 horse Chrysler Starting Procedure/help

The engine is kicking back because of back pressure in the cylinders. This is usually caused by a leaking fuel pump diaphram but can also be caused by a clogged up recirculation system or, more remotely, damaged reed valves.

Change the fuel pump diaphram, it is the easiest thing to do and probably needs it anyway.

John

 

[bashr52]

Re: 75 horse Chrysler Starting Procedure/help

Is the diaphragm something that can be obtained local, or will I end up having to order something? I was told by the previous owner he did replace it after the gas line broke down, and it does work when you apply a vacuum to it off the engine.

 

[john from md]

Re: 75 horse Chrysler Starting Procedure/help

Most Mercury dealers will have them in stock. On the internet they only cost about $3 but a dealer will probably charge you $10.

Ask for the gasket that goes with it also.

These are easy to replace. The fuel pump housing only has a few screws to take out.


John

 

[bashr52]

Re: 75 horse Chrysler Starting Procedure/help

Ok I'll call around tomorrow and find one, thanks!

Can a bad fuel pump diaphragm really cause the engine to kick back? I have a bad one in my Evinrude and all it did was leak gas and not pump, lol.

 

[Skiwi]

Re: 75 horse Chrysler Starting Procedure/help

I have a 1980 75 horse Chrysler <snip>.

I pumped the primer bulb up until there was pressure, set the throttle to neutral warm up, and cranked it over with the chokes closed. It will fire and run for about 1/2 a second, or so occasionally. usually, once the engine fires once, it kicks the starter drive off the flywheel and stops, while the starter just turns in place. It will not stay up if it fires. I can't keep it engaged long enough to allow a good start/restart. Suggestions? Is this the correct starting procedure?

Also, after I pump up the prime and crank it and it fires a few times, the primer bulb is soft again. I tried cranking the engine over without the outlet line to the carbs connected to the fuel pump, and nothing comes out. All the gaskets and such have been replaced in the pump, screen is clear, and if you remove it and apply a vacuum to the vacuum line it pumps fine. Should it be pumping when the engine is spinning off the starter?

Thanks!

I have the same engine, the previous owner used to start it with Ezistart all the time when cold.

I've had no trouble using the normal cold start procedure which is the same as yours except I will "bump" the chokes again if it starts to stumble. I can usually forget the choke about 20 seconds after if fires.

I found adding a second battery helped as well, the extra "omph" makes sure I deliver full amps/volts to the starter.

 

[1983rinker]

Re: 75 horse Chrysler Starting Procedure/help

Is the throttle push forward? I have same motor.

 

[john from md]

Re: 75 horse Chrysler Starting Procedure/help

A leaky diaphram causes excess fuel build up in the lower cylinder which causes the engine to kick back. They only cost a few bucks and only take a half hour to change.

John