doesnt start tiil key is released

[ringmaster]

ok now that my boat is done im getiing ready my cousins boat. i noticed it before but didnt pay to much attention to it. but somtimes when you start it it will just roll over til you let go of the key and then it will start right up. its a 1978 sea ray mercruiser 305 motor with the 898 out drive pre alpha. is it the coil going bad or the ignition switch? thanks.

 

[Don S]

Re: doesnt start tiil key is released

Do you have power to the + terminal on your coil with the ignition switch in the run position? IF not, start tracing back to the ignition switch to find out where you lost power. Should be a white wire on the coil and ign. switch that should have power.

 

[Boatin Bob]

Re: doesnt start tiil key is released

Don...unless I misunderstood him, it sounds like there is power to the coil with key turned to ON or RUN but there's nothing there when turned to Start?

 

[Don S]

Re: doesnt start tiil key is released

Don...unless I misunderstood him, it sounds like there is power to the coil with key turned to ON or RUN but there's nothing there when turned to Start?

Yea, I read that completely backwards.
He needs to check the wire between the starter termianl D and the + terminal on the coil. The D terminal is what puts cranking voltage to the + side of the coil when the starter is engaged. Could be the wiring or the starter solenoid.

 

[ringmaster]

Re: doesnt start tiil key is released

it rolls over when the key is in the start position. somtimes it will start right up but other times it will just roll over unti the key is released and it comes back to the run possition then it will fire. sorry for the confusion don.

 

[mkast]

Re: doesnt start tiil key is released

You can test the ignition switch, jumper the BAT terminal to the ON terminal, turn the key to start, let the key go. If the engine is running, the switch is bad.

 

[ringmaster]

Re: doesnt start tiil key is released

this might sound funny but for some reason it was caused from the batterys being low we put the charger on it to day for couple of hours and everytime i hit the key it started right up. it may still have and issue but its working right for now.

 

[dmcb]

Re: doesnt start tiil key is released

This used to happen on old engines sometimes when the battery was low. It took all the power to turn the engine and didn't leave any to start.
Well that is an old engine. But I meant when I was young. And that is old.
Doug

 

[Don S]

Re: doesnt start tiil key is released

This used to happen on old engines sometimes when the battery was low.

It's even worse on the new EFI engines Doug. If they don't see enough rpm, or too much voltage drop, the ECM will not provide power to the ignition system or the fuel pump. The voltage drop during cranking is why they recommend starting batteries and not deep cycle batteries. The DC batteries will show a lot more voltage drop during cranking.

 

[captk]

Re: doesnt start tiil key is released

check the slave solenoid on the back of the exhaust manifold. Make sure it is giving 12 volts to coil during crank.