Power head removal!

I need to replace the gasket between the power head and lower unit on my 1985 XP150.<br />What is involved in this procedure?<br /><br />Thanks,<br /><br />DoferGofer

Re: Power head removal!

OK DoferGofer...(I was to when I was playing)...Here's what to do. You'll need some way to lift the heads, shop hoist, come-a-longs and a way to grap the head to lift....preferably one that will lift the head by the crankshaft.<br /><br />Once you got that, diconnect the fuel lines inside the pan, diconnect the battery cable, engine harness and TNT leads. Disconnect the control cables. Make sure the pee hole hose is disconnected also.<br /><br />Remove the two small covers below the lower engine pan. There are two screws in front, two screws inside the engine pan and two holding the front cover on you get to once the wrap around cover off.<br /><br />There's a nut and a bolt toward the front of the block under the lower engine pan, two studs with nuts at the rear of the engine block....a slim 1/2" wrench works well here...and three long bolts bolts on each side under the pan to remove.<br /><br />Inside the pan, look for two bolts holding the pan to the block, these will be toward the front of the block. Remove them.<br /><br />Disconnect the shift rod.<br /><br />Hook up the hoist and lift away. If the block sticks, shake it. It'll come lose.<br /><br />For a more detailed explanation with pics, get a OEM service manual.

Re: Power head removal!

Thank you kind sir,<br /><br />I have all of the necessary tools, cheery picker and a wheel puller to connect to the flywheel.<br /><br />The reason for my question is to seek any of the trade secrets since, I am mostly acclimated to automobile type maintenance.<br /><br />The engine has a high speed miss 3300 -3800 rpms going up or down the rpm scale. Also, there is a oily ooze dripping down the outside of the lower unit.<br /><br />Since, I have changed out most of the electrical components and those not swapped out test good. I was advised to replace power head gasket because if its oozing that much down the lower unit, it is also allowing air to seep in the crankcase while running. Any truth that diagnosis?<br /><br />Regards<br /><br />DoferGofer

Re: Power head removal!

Its usually not a problem lifting the motor with the lower unit still on, I find it much easier re-set the block without the L/U attached.

Re: Power head removal!

(Its usually not a problem lifting the motor with the lower unit still on,)<br /><br />I presume you mean the lower unit being left attached to the transom?<br /><br />(I find it much easier re-set the block without the L/U attached.)<br /><br />Now you have me lost. Please explain.<br /><br />Regards.<br /><br />DoferGofer <br /><br /><br /> I find it much easier re-set the block without the L/U attached.

Re: Power head removal!

I mean remove the lower unit of the motor, the foot, the gearcase, whatever else it may be called, from the mid-section. The drive shaft of the lower unit sticks up into the bottom of the crankshaft of the motor. After you disconnect the shift linkage remove the 6 bolts under the cavitaion plate, remove the trimtab and the bolt that is hidden by it, and remove the large bolt that is directly in front of the prop. The lower unit will drop and you can pull the whole thing out. <br />And you will also need a new powerhead base gasket when you set the block back on.

Re: Power head removal!

Ok, you mean drop the gear case the same as if I was replacing the water pump etc.<br />Then the power head can be more easily removed and reattached to the center section?<br /><br />DoferGofer

Re: Power head removal!

Si!

Re: Power head removal!

Hallelujah! We are on the same track.<br /><br />Thank you so much,<br /><br />DoferGofer,

Re: Power head removal!

Dhadley and senior member. What is your take or opinion on a leaking power head gasket other than a unsightly, messy, nasty path of black oozing oil leaking down the front and sides of the lower unit (leg) on a 1985 XP 150, will the leaking power head gasket cause any drive ability problems such as high to mid-range missing?<br /><br />Regards<br /><br />DoferGofer,

Re: Power head removal!

OK, if the oil leaking is showing up on the lower unit -- I'd bet the lower, inner exhaust housing is missing. <br /><br />However, if the oil is showing up on the top of the mid section, just below the powerhead, toward the front and especially on the port side -- I'd bet the exhaust housing is cracked on the inside corner. Kinda common on early to mid 80's midsection. It could be the base gasket -- cant hurt to repalce it. If the leak is as described.

Re: Power head removal!

The inner exhaust housing has not been replaced and the leak is as described, in fact you sound like you seen my engine. You didn't mention but, is there any drive-ability problems with this leak, or the only concern is the messy appearance.<br />Just wonder if I am working something that I could put off until I get rid of my 3300 -3800 rpm miss.<br /><br />Regards,<br /><br />DoferGofer

Re: Power head removal!

If you decide to remove the powerhead with the gearcase still attached, be careful if you need to "shake" the powerhead to break it loose. Remember the drive shaft splines are engaged into the bottom of the crankshaft and could be damaged. That could create problems you really don't need.

Re: Power head removal!

Thank you kind suh!<br /><br />Another good explanation & point, for a novice like me to know and remember.<br /><br />Regards,<br /><br /><br />DoferGofer

Re: Power head removal!

hello<br /> that oily mess can alsobe a lower crank sealleaking. it is possible toreplace the sealby pulling the lower bearing housing. its not easy but its doable. I made a fixture to replace the lower bearing without a crancase cover removal. once the powerhead is off inspect everything carefully.

Re: Power head removal!

The problem created by a blown base gasket is that exhaust can filter up into the block area and into the carb intakes and the engine starts breathing is own exhuast. Is there anykind of mess in the pan or is all the mess on the outside of the engine?<br /><br />Dropping the lower unit before pulling the power head gets the drive shaft and shift rod out of the way....that's all. Re-installing the lower unit before putting the power head back on can help guide the power head into place.....sorry for not being clearer on that. Having the lower unit off will also give you the opportunity to check the water pump and exhaust seals for that area. <br /><br />Have you done anyother checks to the block other than electrical? What do the plugs look like...any of them cleaner than the others? Are you sure it's a miss? When were the carb last overhauled and fuel lines/hoses checked/replaced? Have you done a compression check?<br /><br />Might seem like strange questions Dofer but surging rpms don't really make it a miss. At that rmp range, it's possible that you could have a partially plugged imtermediate jet or maybe some kind of junk floating around in the float bowl. Take care of the original problem first and we can go from there.

Re: Power head removal!

Originally posted by rodbolt:<br />once the powerhead is off inspect everything carefully. <br /><br />I will check it closely.

Re: Power head removal!

Originally posted by OBJ:<br /> The problem created by a blown base gasket is that exhaust can filter up into the block area and into the carb intakes and the engine starts breathing is own exhuast. Is there anykind of mess in the pan or is all the mess on the outside of the engine?<br /><br />No, there is not any mess inside to pan although, there is a little seepage at rear center bolt at the power head and base.<br /><br />Originally posted by OBJ:<br />Dropping the lower unit before pulling the power head gets the drive shaft and shift rod out of the way....that's all. Re-installing the lower unit before putting the power head back on can help guide the power head into place.....sorry for not being clearer on that. Having the lower unit off will also give you the opportunity to check the water pump and exhaust seals for that area. [/QB]<br /><br />Thank you, I understand more clearly now.<br /><br />Originally posted by OBJ:<br />Have you done any other checks to the block other than electrical? What do the plugs look like...any of them cleaner than the others? Are you sure it's a miss? When were the carb last overhauled and fuel lines/hoses checked/replaced? Have you done a compression check?[/QB]<br /><br />Nothing other than electrical and cleaning the carbs. I done a compression check, all cylinders are within three or four lbs of each other.<br /><br />Originally posted by OBJ:<br />Might seem like strange questions Dofer but surging rpms don't really make it a miss. At that RPM range, it's possible that you could have a partially plugged imtermediate jet or maybe some kind of junk floating around in the float bowl. Take care of the original problem first and we can go from there. [/QB]<br /><br />The carbs were cleaned last spring. Since I am pulling the engine down again I will go over the carbs again. Just to mention. The carbs were clean as a pin when I torn them apart last spring. But, I will check them again.<br /><br /><br />