Fuel pump -rectifier-stator????????

[e92]

Hello everyone , I need help ,I recently bought a used boat that had been sitting up for about a year and half.It has a 75 horse(4 cyl.--2 carbs) Mercury ,mid 1980's .When I bought it I knew that the motor had some problems.When I pumped the bulb to start it gas poured(new gas) out the front of one of the carbs,I thought the float was stuck so I tapped on the side of the carb and sure nuff the leak stopped ,the bulb got firm and it cranked up and idled great. so I took her to the river thinking all was well,it would still crank and idle great but when i would try to open it up it would for a few seconds then it lose power and finally quit running .I could recrank it and it would do the same thing.So I took it to a dealer for them to take a look.<br />He rebuilt the carbs ,replaced the fuel filter, the stator and the wiring harness(the wires were in VERY bad shape)<br />Heres the problem I have now---when I crank it now ,it does good for about an hour or so ,but any time that I turn it off after that it is very hard to start and nearly imposible to keep it from stalling when I put it into gear, but when I do finally get it in gear and the rpm's up just a little it will run great until I shut it down again ,then I have to start all over again.I found out on my last trip to the lake that it is not charging at all ( I borrowed a partially charged battery from him to finish the day out , and it may be my imagination but it did seem to help my problems for awhile,it also idled at a higher rpm when I first installed his battery),My mechanic says that I need a rectifier to correct this and he also feels like this could have something to do with my idle/stall problems.<br />So heres my questions .....does the motor need any extra power from the battery when you first accelarate from an idle ?could the new stator he installed be the problem?What about the fuel pump ,it was not replaced and I have noticed at times it does not have a whole lot of gas in it while its running ,should it stay close to full all the time ?<br />Any ideas ????<br /> Thanks in advance<br /> Art

 

[wilde1j]

Re: Fuel pump -rectifier-stator????????

Art, a lot of motors will run poorly on a less than fully charged battery. It's easy to determine if the battery is being charged. Run motor at idle and measure voltage across the battery terminals. You should get 13.5 to 14.5 vdc. If it measures 12.7 or less, the battery clearly isn't being charged. From there, you need to find out specifically what component(s) are causing the condition. For that, you should get a shop manual if you're doing it yourself.

 

[e92]

Re: Fuel pump -rectifier-stator????????

Thanks WildOne---I did check the voltage when it was running so poorly , it was less than 12 ,more like 11.6 or so and that was at an idle or reved up ---do you think that is low enough to cause my stall/idle problem ???<br /> thanks again for your help---Art

 

[almost retired again]

Re: Fuel pump -rectifier-stator????????

Hi ENG92,<br />Most newer engines no longer have<br /> battery ignition. I don't know what you have except that you said it was in the mid 80's by that time it should be a CD ignition system. If so the stator serves two purposes; to charge the battery and supply the voltage nessary to charge up the condenser for the ignition. These two functions are independent from each other. The battery's main function is to run the starter and all accessories. The windings in the stator for chargeing the battery puts out an AC voltage that is then rectified to a DC voltage to charge the batterys. Also wound on the stator are windings that again put out an AC voltage that is rectified in the switch boxes to DC to charge the condensers in the switch boxes. Neither of these voltages should effect the other. I do think that you have a charging problem from what you have said. It could be in the stator, but most likely it's a bad rectifier. I dont think anyone can help you much until we know the model and serial no. of the engine so we can know just what you have.<br />Let us know and someone will probly be able to help you.

 

[e92]

Re: Fuel pump -rectifier-stator????????

Thanks for the info Almost ----My serial # is OA994933---do you think replacing the rectifier will have any effect on my idle/stall problem? oh and also the stator has just been replaced--Thanks so much for the help---Art