1998 Mercury 200 EFI

[Ken Pearson]

Hi guys,

I still have some problems with the motor. I replaced the fuel pump the ball, the filter and sparkplugs on this thing and I still have problems with getting it to plane out. The boat is a 1997 Nitro 896 Savage, rated for a 200hp. I currently have a Quicksilver Trophy 48-825940-24P (4 blade) prop on the motor. Also when I try to pull the baot up onto the trailer it boggs out on me. Sometimes when I am taking off it sounds like it wants to bogg out but it will finally catch up to itself and run. It acts just like the plugs are starting to foul. Could the oil mixture be wrong? Once it does get on plane the boat runs great. Any ideas? Should I try changing the prop to a 3 blade prop? If so what pitch should I use?

Thanks for all the help in the past.

Ken Pearson

 

[marinegrh]

Re: 1998 Mercury 200 EFI

did you just get this boat, or has this problem just arose, do you have access to a test prop, , whats your fuel rail pressure, have you gone down in pitch, three blade or four blade, doenst matter as long as its the right diameter and pitch, a good dealer should be able to let you borrow a prop to test out if its a propping issue, i would like to know if you have good fuel pressure and spark, just some thoughts

 

[Ken Pearson]

Re: 1998 Mercury 200 EFI

No, I got this boat about a year ago and it was running fine, but started to run a little rough so I took out the bosch plugs and replaced them. I originally put in champion plugs but the fouled out pretty quick. I finally found NGK plugs replaced the champions and it ran a little better at high speed, but would bogg out when first taking off and when trying to put it on the trailer. I replaced the fuel line ball and the fuel pump and put new NGKs in and it appeared to run better for a month or so, then right back to square one. Not really sqaure on it runs great at high speeds and strats a lot better but still this loss of power. When I bought the boat the guy I bought it from had just replased the prop shaft seal and the dealer told him that the prop wasn't the right one for that boat and motor. I don't know what else to do. I think that I can get my hands on a prop I'll try that, but I really don't think that that is the problem. For some reason I think that there is a power loss somewhere. How do I measure the fuel pressure and the and spark?

 

[Don S]

Re: 1998 Mercury 200 EFI

Why did you change the fuel pump? Was the pressure low? Have you tried to run the engine on a remote tank to try to eliminate the fuel system?
Might want to do a compression check on it before you do any more parts changing, and check that you have good spark on ALL 6 plug wires.

 

[cgBosun3]

Re: 1998 Mercury 200 EFI

I used to sell and deliver Nitro boats at a dealership - a 24" pitch prop is a lot on that boat. It's like trying to start your car in overdrive on a hill. A lot of bass boat owners think you can get a higher top speed just by loading pitch on your prop. Assuming the engine is running correctly (BIG assumption!) I'd look at trying a 21-22" pitch prop.

 

[Ken Pearson]

Re: 1998 Mercury 200 EFI

The reason I changed the pump was that when sitting the boat would die at idle, the ball wouldn't stay hard and when taking off after sitting for awhile it would run out of prime. This was after I changed the ball and the anti- (waht ever it is called on the tank). When I first changed the pump and changed the plugs it ran like a champ. But after awhile it acts as if it wants to foul the plugs. I'll try the remote tank thing it might be the fuel line in or out of the tank.