mercruiser 898 fouling plugs

[ringmaster]

i have a 78 searay with a mercrusier 898 305 i just put a second set of plugs in it because it keeps fouling them after about a 20 min ride. when i took the first set out i found 3 plugs soaked in gas. what would cause this to keep fouling plugs? also when i put a new fuel filter on the gas kept running out in a steady stream until i got the ne filter on the tank is in the bow is it suppose to do that? one last question when it is in forward or reverse and i go back real slow to neutrel the motor shuts off but if i move fast to neutrel it will stay running is there a problem with the neutrel safty switch? thanks

 

[erikgreen]

Re: mercruiser 898 fouling plugs

I'm not an expert mechanic compared to some here, but I'll make a guess at this.

Gas is not supposed to come out in a steady stream from the carb when you hook up the tank. The carb meters the amount of gas according to engine rpm, and mixes it with air to get the right combustion mix into the cylinders.

If your plugs are fouling, you're getting too much gas into the cylinders. From the sounds of things you need to adjust or fix your carb.

Erik

 

[WillyBWright]

Re: mercruiser 898 fouling plugs

The gas tank should have an antisyphon valve at the top of the pick-up to prevent gas fronm running if a leak should occur. That would shut off the gas flow when you replace the filter.

The neutral safety switch only affects the starter. It doesn't affect running. You might have a stiff shift cable through the transom.

And it sounds like you need a carb rebuild.

 

[Haut Medoc]

Re: mercruiser 898 fouling plugs

Welcome to iboats......
All of the above is true......
Your shifting symptom is most likely the lower shift cable getting towards the end of its' service life.....
The shift interrupt switch is actuated by that cable, when it remains closed to long, it will kill the engine......​

 

[ringmaster]

Re: mercruiser 898 fouling plugs

yeah i ran into an old friend today and talked to him about i thought real hard and said the heck with it and let him take it to his shop and fix it right as for the tank he believes the antisiphon valve was taken out. he did say that the cabe does need to be replaced since it was doing it in both gears. is $250 to much for labor and parts to fix it? i didnt think it was since i know what the parts cost.

 

[Haut Medoc]

Re: mercruiser 898 fouling plugs

Two hours & 50 bucks for the cable.....​

 

[ringmaster]

Re: mercruiser 898 fouling plugs

$250 is for the carb rebuild new plugs him to test and tune the carb and cable.