Engine problems

[boston_jake01]

I have a 1989 power play with volvo aq271 gm 8cyl. motor. the problem I'm having is it starts up and runs ok at low rpm, but when I accelarate it starts to sputter and surg. Also it seems to have a hard time starting after it is warm.<br />here are the things I have donefor it so far it was worse but still has some problems the carb use to leak in the barrals (4 barrel Holley).<br />I replaced the carb, drained the fuel tank, replaced water seperator, added inline fuel filter, replaced spark plus, wires, cap, rotor.<br />I also noticed oil in coil and tighened the screw which was loose. I am thinkin of replacing the coil could this be the problem, any ideas<br />Thanks

 

[ReeReeJr]

Re: Engine problems

Possibly need a new fuel pump; the diaphram may be failing..

 

[Gary H NC]

Re: Engine problems

The coil is cheap enough to try it too..<br />Did you replace the points and condesor?<br />Oil in the coil? on the top? sounds like its bad..

 

[boston_jake01]

Re: Engine problems

I don't know if I have point and condenser.

 

[paulie0735]

Re: Engine problems

jake, is this a new boat to you or did this just start to happen?

 

[searay3]

Re: Engine problems

Replace the coil if you have any doubt. Bear in mind, with the Holleys, if it backfired, the power valve is probably blown. It's in the front bowl.

 

[boston_jake01]

Re: Engine problems

This boat is new to me, I replace the holley carb with an edelbrok carb and its made a difference it ran smother and no dripping in carb, but still running rough at 2000 and above rpm.

 

[Don S]

Re: Engine problems

Did you set your timing and check advance timing?<br />Might do a compression test and vacuum test.<br />How did the old spark plugs look when you took them out? Any indication of water, oil, other?<br />You should also check your boats fuel system like this<br />Have you done an ohms test on your plug wires?

 

[boston_jake01]

Re: Engine problems

I am going to check the timming tomorrow (Its's raining bad here now) and replace the coil. I didn't notice anything other than fuel on the old plugs I figured it was due to dripping of old carb. I never thought about vacuum test or ohms test I will see what happens after tomorrow work. thank you for all that info.<br />Crossing my fingers I would like to enjoy the boat this year..

 

[paulie0735]

Re: Engine problems

Jake, the edelbrock requires a special adapter plate to function correctly on a stock chevy manifold, if you don't have the correct plate or are not sure than google edelbrock and you will find all the info you need to ensure your conversion is done corectly. Good luck.

 

[boston_jake01]

Re: Engine problems

ok thanks

 

[boston_jake01]

Re: Engine problems

ok installed the new coil and still runs the same<br />I tried just adjusting the timing without the timing light just to see if there was a difference there was some difference but still not right I was able to get it to go up to 3000 rpm without roughness but it got bad after that and still after it got warm it was slow turning over and then wouldn't start.<br />sat. I will do vacuum test and time it with the light.

 

[Don S]

Re: Engine problems

You need to set the timing properly, and check to make sure the advance is working. Are you sure the trottle plates are opening all the way?<br />You seem to want to throw new parts at it without finding a cause.<br />Do the troubleshooting and proper setup and it will work.

 

[boston_jake01]

Re: Engine problems

Ok I will Check and time it correct.<br />I don't know how to check the advance there is no vacuum hooked up to it, how do I check this?<br />The carb plates are opening atleast the primaries,I don't think the secondaries are supposed to unless you floor it? right?<br />Thanks

 

[lilmandavis]

Re: Engine problems

its mechanicaly advanced with flyweights inside the dizzy. vacum secondaries. you should see a steady advance curve with the light through the rpm range.

 

[boston_jake01]

Re: Engine problems

what is a dizzy, what do you mean "vacum secondaries. you should see a steady advance curve with the light through the rpm range."

 

[lilmandavis]

Re: Engine problems

*distrubutor

 

[lilmandavis]

Re: Engine problems

dizzy is what we hill billies call distrubutor! and the secondaries on the carb, open when the engine is at a certain rpm. and the curve is when its ideling the timing is about ten degrees, but when you throttle up the timing is advanced from the flyweights inside the distrubutor. youll see the timing creep up to about 30 degrees or so at wot. if it doesnt advance or goes way out that indicates that theres a problem. if the springs are shot its goin to idle fine but run crappy at higher rpms

 

[boston_jake01]

Re: Engine problems

so how do I check the mechanical advance? and should the secondaries not open when the throttle is opened slow and not floored?

 

[boston_jake01]

Re: Engine problems

now would the secondaries open if the rpm are not able to rise correctly such as sputtering?<br />what would cause the secondaries not to open?