1989 XP150 runs rough

[X270]

Good evening,

New to me XP150 two stroke runs a little rough.

Gave it the seafoam shock treatment, one bottle in a gallon of gas plus the oil.

Let it run and occasionally, it would puff some smoke back through what looks like the head gasket? I'm sorry, outboards are new to me.

What's my next step? Where can I find a factory service manual?

Can't upload a picture, so here's a link to a video I took.

https://youtu.be/F1mc14UqTiU

-Ross

 

[flyingscott]

I don't think that is a head gasket. That is an access cover take it off and see if the gasket is bad. The motor miss looks like a lean sneeze replace the gasket on the cover and see if it improves.

 

[emdsapmgr]

Also possible it is the gel seal leak between the two crankcase halves..

 

[Faztbullet]

My bet is transfer port cover gasket.......see a lot of this on the crossflows.

 

[X270]

It is where the two crankcase halves meet.

How involved is this?

 

[racerone]

It may well be the transfer port cover !---Replace that gasket first.----Just 6 screws and a $3 gasket.---If it is in fact the crankcase joint the powerhead will have to come off and the crankcase cover will need to come off----Lots of work.

 

[X270]

No Title

 

[racerone]

Replace the tranfer port cover gasket.----Cheap , cheap to do.-----Rough running ?----Post values of a compression test first.

 

[Joe Reeves]

It is where the two crankcase halves meet. How involved is this?

If this is the case, you'll need to dismantle the engine.... discribe exactly where that gasket is.

 

[racerone]

There is no gasket on the crankcase halves.---As stated a number of times----Replace the bypass cover gasket !

 

[Joe Reeves]

There is no gasket on the crankcase halves.---As stated a number of times----Replace the bypass cover gasket !

Quite true... BUT... if smoke, crankcase pressure, anything is leaking, puffing out, whatever, at where the forward portion of the crankcase seats to the rear section of the crankcase, although there is no gasket at that area... there is a sealer between the two (Gel Seal) and it is not sealing. As mentioned previously, a leakage in this area necessitates dismantling the powerhead somewhat in order to correct this problem.

Hopefully you (X270) are mistaken and the leak is as "racerone" suggests... in the bypass cover.