Compression test on 95 sportster Engined Dead?

[cheappc]

Ok, I went ahead and bought a compression test kit, I think I didnt do it correctly, but I:

1. Removed 1 spark plug and placed the spark plug cable on the thing-amajik that it bolts unto to test.
a. It showed 150 on the compression test.

2. Put the above spark plug back in, removed the second spark plug, bolted the spark plug wire on to the thing-amajik that it bolts unto and:
a. It showed 0, nothing?

Ok, after reading other posts, it seems i screwed up the test, that I had to remove both spark plugs, place them on the thing-amajik, and test each cylinder??

In anycase, the top cylinder shows 150, and the bottom 0... I am going to retest again tomorrow...

You think the motor died, or you cant say anything because the test is wrong?

 

[seadooya]

damn homey, thats a bummer....looks like, when yuo purchased the boat, how i found those little oil injector lines broke, that it came back to "harbor" the motor...think it was just a matter of time, slick.

 

[phough5757]

Rotory valve

I'd check the R-V.
It gives the same thing on a compression test.

 

[Dr Honda]

Well... even if you screw up the test... you should still see better than 0. Only way to get that low is if the piston shattered.

 

[cheappc]

What does check the RV again mean?

Ok it is a bummer if the motor died, apparently the gentleman that sold me the boat probably knew it was coming, and didnt want to shell out any more money for a rebuilt engine...

So I find myself at this junction, the boat is in pretty good shape for a old boat, I dont have 12 to 20 thousand for a new boat. I seen one of those 657x rebuilt engines with a 2 year warranty for $699 look here.

I probably can find it cheaper hopefully. Do I do a rebuild on my motor, or do I just buy another motor and hopefully you seadooya can install it for me?

 

[cheappc]

Or do you guys think I should upgrade to a 717 engine,

1. Is it possible?
2. Is cost effective?
3. Major improvement over my current setup?

 

[parrothd]

You need to have all the carbs rebuilt, have the oil injection system tested & fixed if needed, then rebuild the top end.

That other website sells complete motors with 1 year warranties and top end kits. Personally I'd recommend the complete engine, if you mess up the install or don't fix the issue that caused the other engine to die they'll replace it...

 

[unclejay]

Tdc ?

Was the second cylinder at top dead center ? If it was on intake or exhaust portion of the stroke, zero compression.

 

[cheappc]

im not sure what you mean, top dead center?

The Cylinder on top working on the motor with my knees on the seat looking into the engine the top one is reading 150 the bottom one 0, however, I havent done the test again with both wires plugged in to the harness and both spark plugs removed, will do that asap.

Seadooya I over heard that you can rebuilt these things, or install a new one? How much is something like that?

 

[seadooya]

Seadooya I over heard that you can rebuilt these things, or install a new one?
How much is something like that?

gotta take a look to see what went, my friend, then we;ll go from there. FULLBORE look'n real ttempting, but SBT for the price of a 657 (got one for customer in garage now), cant beat it dude.

 

[cheappc]

what does that mean? FULLBORE and SBT mean?? lol

 

[seadooya]

fullboreonline.com or shopsbt.com

Both are rebuild companies, homeboy, just sbt has bettewr price for the 657 motors....I'll be that way friday, the nhad plans on bounc'n to river...didnt mean to rub it in, bud...

 

[cheappc]

ok I THINK my engine is dead......

I redid the test correctly this time and top first cylinder showing like 5, and the 2nd bottom cylinder is showing 150...

What is TDC or or R Valve?

 

[cheappc]

Also which is better and more economical?


1. Rebuild my own engine, what is the approximate cost?

2. Buy a rebuilt engine and installing it?, what is the approximate cost?

Including labor and everything else?

 

[phough5757]

R V is Rotary Valve

Between the carb and Cylinder is a Rotary Valve. Kinda like an intake valve.
The R V is driven by the crank shaft. I cant remember if it can be seen through
the Carbs. With the plugs out try to turn the motor by hand. This is done by
removing the grey cover at the rear of the motor. The large disk under the
cover is the PTO. Power take off. Grab the disk and turn the motor CCW.
Counter clock wise. At the same time shine a flashlight down the carbs to
see if the RV turns.If it cant be seen, try putting something down the Carb
like a short piece of thin wire or a wire tie. If Your up to it , Remove the Carbs
to see if the RV is moving.
If its not moving, the Brass gear is striped. Very fixable.I have done the fix.

 

[cheappc]

OK I can do that..

I remember putting in some grease on the "PTO" with a grease gun...

Sorry for the dumb question, but what would this do?

 

[voodoo]

The grease is for the hull seal/bearing and the pto splines also have this fitting - this lubrication has nothing to do with the motor sliding or rotating parts - the motor lubrication comes from the OEM injection system that has spray nozzles running from a pump driven by a shaft inside the rotary vavle cover - great picture by phough, but sometimes what happens in a boat transfer is so much exictement the type of oil is overlooked entirely and mixing 2stroke oil is a big gamble - many times it forms a gel that the pump can no longer spray inside the motor either blocked nozzles or the small oil lines get plugged with the gel product - it is like when you smear jelly on the outside of the jar, flush it all with kerosene to restore the pumping action and then choose and stay with oil from a reputable supplier, when you run your first bottle empty cut off the front and leave it in the glove box so you can always get the same type.

 

[parrothd]

Also which is better and more economical?


1. Rebuild my own engine, what is the approximate cost?

2. Buy a rebuilt engine and installing it?, what is the approximate cost?

Including labor and everything else?

Buy an sbt rebuilt engine, comes with 1 year no fault warranty, be sure to have the carbs rebuilt and fuel system checked out..

 

[cheappc]

wow guys thanks so much, I will do the rotary valve check this weekend...

 

[parrothd]

Did you buy a compression tester?

You installed it in the spark plug hole and turned the engine over? then repeated in the second spark plug hole?

1 cylinder showed 150psi the showed 0psi?

Engine is shot, nothing to do with the rotary valve, don't bother testing it,

You need to rebuild the top end, or at a minimum the cylinder showing 0 compression. You also need to figure out why that cylinder is has no compression, which is probably from a carb issue running the boat lean and seizing the piston and causing you to have no compression in that cylinder.

 

[cheappc]

Did you buy a compression tester?

You installed it in the spark plug hole and turned the engine over? then repeated in the second spark plug hole?

1 cylinder showed 150psi the showed 0psi?

Engine is shot, nothing to do with the rotary valve, don't bother testing it,

You need to rebuild the top end, or at a minimum the cylinder showing 0 compression. You also need to figure out why that cylinder is has no compression, which is probably from a carb issue running the boat lean and seizing the piston and causing you to have no compression in that cylinder.

What does carb issue & running lean mean?

Ive rebuilt my carbs just recently....

Thank you..

 

[parrothd]

When owners fail to do maintenance on the fuel system, the carbs can get "plugged" up and fail to operate properly. The carbs allow a ratio of air & fuel into the motor to run and keep the engine cool.

If the carbs get plugged up with debris in the filters they don't allow enough fuel into the engine, which causes it to run excessively hot (Lean), a lean running engine will cause the piston to expand and then get stuck in the cylinder.

When the engine cools, the piston becomes unstuck. The owner then starts the ski and does this a few times until the engine is damaged an no longer runs.

Carb issue = lean = bad = Hot engine = stuck piston= 0 compression = engine doesn't run..

 

[cheappc]

I guess that wasnt the issue... I just rebuilt my carbs, but thanks a lot for that information, now I know....

Yes, its stuck at 0 compression on the second cylinder...

 

[phough5757]

Rotary Valve.

If the RV has wiped out the Brass Gear the RV could have stopped with
with the port open. You will get NO compression in that Cylinder.
Let Me ask You to put Your hand over that Carb while You are cranking
the Engine with the spark plugs in. Do You feel any air blowing from the
Carb? It did on Mine. In the Photo,sorry about the quality, the Engine was out
to repair the RV.
I think You could do it also.
Where do You live, I'll come and help.

 

[cheappc]

Sorry I havent written back, im in Los Angeles, Downey, CA

maybe too far for you? lol.. thank you though I really apreciate it!