xr2 lower unit

[popee1950]

1985 xr2 150 hp. serial# a167228. grinds going into gear. will not plane. strong spark on all cyl. rebuilt fuel pump, carbs, reset floats, new stator. running 26 stainless prop. marked prop and it's not slipping. Was getting on plane before taking motor off boat to replace transom. Metal on foot drain plug. Are the the gears in the foot going out? Time for lower unit rebuild? Thanks Lee

 

[James R]

Re: xr2 lower unit

The Revs at idle before engaging the gears should not be more than about 1100. The shift needs to be snapped into gear. Don't try to feel it in. Need to pull the lower unit to feel if the shaft bearings are good. A bad lower can prevent the boat planing. Not unusual to get a tiny amount of metal on the plug but if there is a bunch then you may have a problem.
What shape are the compressions in and is it firing on all cylinders

 

[Faztbullet]

Re: xr2 lower unit

How long did motor sit while transom was repaired? Are cables installed corectly? Is throttle opening all the way? A 26 pitch is a awful big prop for a XR2 unless its a real light boat.

 

[popee1950]

Re: xr2 lower unit

Motor sat for about a year. Prop was on motor when i bought it. Mounted on 17 ft lazer 1985. What would be the best pitch. Throttle is open all the way. Cables are correct. It just revs high but will not get anywhere near plain. Like prop slipping. Motor is lowered all the way, thought maybe it wasn't getting into water enough. Thanks for the replies.Keep them coming.

 

[aussieflash]

Re: xr2 lower unit

Post photo of stern with motor trim down.

 

[popee1950]

Re: xr2 lower unit

update on above motor.Did comp. check. cyl 1 50, cyl 3 48, cly 5 53, cyl 2 58, cyl 4 61, cyl 6 60. no way of knowing how accurate the gauge was. where do i go from here on the compression. could it be head gaskets? Also have five inches from bottom of boat to bottom anti ventlation plate. Prop.would be about 3/4 clear water with motor all the way down. Any help? Thanks Lee

 

[mwe-maxxowner]

Re: xr2 lower unit

I have an 84 mercury 150 xr2. I believe stock compression is around 120. My top left is 60 Pei, all others are 120-130. I'm planning a rebuild this winter even with these numbers. Boat still runs great though.

The water pickup is above the prop. If your prop isn't even all the way under water, you aren't getting any water to the engine.

 

[popee1950]

Re: xr2 lower unit

if gauge is correct, looks as though i need a rebuild.

 

[popee1950]

Re: xr2 lower unit

clarifcation, foot of motor goes down in water far enough. propeller just doesn't go below hull all the way.

 

[popee1950]

Re: xr2 lower unit

any other thoughts

 

[Chris1956]

Re: xr2 lower unit

Popee, I will guess your compression gauge is inaccurate. The compression numbers you cite are probably too low for the motor to run, if they are accurate. Also, I would be surprized if you could plane with that 26P prop. I recommend you try a 21P prop and see how that works. I ru a 21 Rapture on my 16 footer with a 135HPV6. I tried a 23P prop, but I like the 21P a bit better.

 

[popee1950]

Re: xr2 lower unit

Thank you chris. That makes me feel better. I'll try another gauge and if that checks out i'll go with a 21p. Will give up date later. Lee

 

[popee1950]

Re: xr2 lower unit

Just got around to taking heads off. Cylinder wall look ok, no gouges or pits that i can see or fill. There is slack on pisons when i push them from side to side or up down useing light pressure. Is this normal or should rings hold them fairly tight in place? Any thoughts ? Thanks Shouldn't have said up or down just side to side.

 

[jimmbo]

Re: xr2 lower unit

The piston is not round when cold and will expand to a round shape when it gets hot. Did you ever get around to testing compression with a different gauge before you pulled the heads? Why did you replace the transom? A few pictures of how the motor sits on the transom (taken from the side at the level of the prop) would go a long way too.

 

[popee1950]

Re: xr2 lower unit

 

[popee1950]

Re: xr2 lower unit

Let me try a couple more pictures now that i got it fiqured out.

 

[Chris1956]

Re: xr2 lower unit

So you have one of those hubless props. That may be the issue. I used a 4-1/4 hub prop on my 135HPV6 Merc (has a 4-3/8 hub), and although I could plane, the revs would be very high all the time from ventilation. I recommend you try a 21P 4-3/8 hubbed, conventional prop.

 

[popee1950]

Re: xr2 lower unit

could you tell me what is ment by hubless and hubbed .

 

[Marathon Man]

Re: xr2 lower unit

That is a "chopper style prop", made for fast top speed but not hole shot. Try one of the props mentioned above. Change lube in lower unit, be sure to use new o-rings on oil plugs, and then check again after a few hours run time. Come back and tell us what the results were.

 

[popee1950]

Re: xr2 lower unit

ok thanks