XP150 Bad Idle then Bogs Down on Acceleration

[Staz]

Hi All,

I have a 1988 Evinrude XP150 and have a question I hope someone can answer or steer me in the right direction to finding a solution. The spark plugs are Champion QL77JC4 and I?ve always had a little trouble with it idling, but recently I needed to change the fuel/VRO pump which I did and installed the new 4-wire model. At the same time I replaced the fuel filter and any bad hoses or clamps. The installation went well and the boat runs fine at higher RPM, although it seems to use more oil than before. Now when I bring it to idle it will idle fine for about 2-3 minutes then slowly dies out, if you keep it in gear it will idle roughly but stay running, but when you give it full throttle (as when pulling up a skier) it just sits and bogs down at about 1500-2000 RPM until you back out of the throttle and accelerate much more slowly (like it is loaded up, similar to my old 2-stroke Moto-X bike). The motor starts fine after stalling but usually needs the idle lever pulled up to stay running. I changed spark plugs twice with no luck (both times QL77JC4), although after it idled for a while the plugs were a bit wet, after a full throttle run they look the right color. The only thing I noticed was on one full throttle run at 5300 RPM I went to lower the trim/tilt and I saw the tack drop to 0 RPM then immediate go back to 5300 RPM. I tried to reproduce this but could not, so I only noticed one time and not sure this is related to the problem. Any ideas? Sorry about the long description but I figured it might help solve my problem.

Thanks for taking the time to read this and any help would be appreciated.

-staz-
d_staz@yahoo.com

 

[tashasdaddy]

Re: XP150 Bad Idle then Bogs Down on Acceleration

i think you need to totally clean and rebuilt the carbs. and do a link N sinc, step by step, from the manual

 

[Staz]

Re: XP150 Bad Idle then Bogs Down on Acceleration

i think you need to totally clean and rebuilt the carbs. and do a link N sinc, step by step, from the manual

Thanks tashasdaddy,

I thought I might have to do that anyway but didn't know if anything electrical might possibly be the cause. I have checked the coils, no leaks or excessive heat, and spark plug wires which look fine and the plugs are getting good spark. Compression is good and timing is fine, battery is new and charging circuit is working correctly. It was also decarbed about 20 hours ago (heads off, everthing cleaned).

I saw in another post a question about spark plugs (and asked about this same question). The original manual calls for QL77JC4's with a alternate of L77JC4. Any ideas of what's best? What are the differences in the two?

Thanks again for your reply.

-staz-