Re-build 40 hp with 130 compression????

[FixOrDie]

1987 40 hp Evinrude motor. (E40ELCUD)

I have a motor that I have done the following to:

1. Cleaned carburetors.
2. Replaced fuel bulb.
3. New water pump.
4. Changed lower unit fluid
5. Checked compression. 130 psi in both cylinders.

I spray a little starter fluid and she cranks and runs pretty good. When I put the lower unit back on after water pump, It ran backwards while in forward. I dropped the lower unit and set it all to neutral and re-installed it and everything seemed ok. I took it out for a short trip and had no top end power. It seemed that fuel was not getting to engine and it just putted along. This is when I replaced bulb and hose and added fuel filter. I noticed the Tell Tell was not peeing also.(on hose clamped to lower unit) I dropped it again and made sure key was in place, re-installed the lower unit and still nothing from the Tell Tell.

I took it into the shop to let them fix it (I'm assuming it was going to be simple) and to do a general check out on the motor. The shop says that they did a pressure test on the cylinders and that they were leaking down. They are calling for a re-build. The owner is super technical and very helpful during my quest to learn to fix it myself. My question is this. (are these).

1. I have never heard of a recommendation to do a leak down test when buying a used motor only compression. It seemed odd that it had I assume great compression but now needs a rebuild.
2. If this is the case, would it be possible to replace the rings or something less drastic taking into account the 130 psi compression reading?
3. What would be allowing for 130 psi compression yet still loosing sustained pressure ?
4. If re-build IS required, what particular shop manual would you recommend that details how to accomplish this along with technical things that need to be done? ie: How much to bore, what size piston for that bore, any settings and clearances that might be required........and so forth.

Thanks to guys like you, guys like me can learn to fix things ourselves. Much more satisfying than dropping it off and picking it up already repaired!

Thank you in advance for your input.

 

[racerone]

130 is not that bad.----Are you pushing the key in and holding it in while cranking it over ?----Sounds like the cables were mixed up at the motor.----Tell tale will not pee if motor is not running while hose is clamped on it.----Have you checked spark ?----Have you checked flywheel key ?-----Some orderly trouble shooting needs to be done here.

 

[FixOrDie]

I push in the key and the primer seems to be adding fuel to the carbs. The primer seems to be kind of melted like maybe it was once overheated.

After I dropped the lower unit, set it to neutral and the controls to neutral and re-installed it, the running in reverse while controls were in forward was fixed.

I checked the spark on both cylinders and they were firing just fine.

The motor was cranked while checking Tell Tell.

Not sure about flywheel key.

 

[FixOrDie]

What are your thoughts on the pressure test on the cylinders leaking down ?
I'm not sure how long it took to leak down.
Would this be a reason to re-build in light if 130 psi compression?

 

[racerone]

Test the primer !----If it is stuck open it will cause grief.----Inspect the flywheel key.----Or put # 1 cylinder to TDC and see where the timing pointer is.----I do not believe you need to rebuild !!----Do some inspection and trouble shooting here.

 

[FixOrDie]

Shouldn't TDC be at 0" on the pointer?
Do you happen to know if timing WOT=19' <4'> ?
I don't have any manuals yet.
I found a forum post that said 19' and the only difference in the 40 and 50 are carb jets.
That was interesting.

 

[racerone]

Sorry ----But it is up to you to see if it is actually where it is supposed to be !!!------Trouble shooting needs to be done by you.----Over and out.

 

[Tim Frank]

Shouldn't TDC be at 0" on the pointer?

It should be....but if the key is sheared it will not be. That is why Racer suggested you check.

 

[kbait]

You can’t assess waterpump function by running on muffs -period. Run it in lake, or barrel deep enough to submerge waterpump and try again. If not peeing, clear out indicator hose and try again. Still not peeing, let run and check head temp while warming. When it gets to 140 or so, thermostat should open and discharge some water out the exhaust relief ports in back. If it does that, and temp doesn’t rise further, your motor is cooling properly and the indicator system is plugged somewhere.
Melted primer likely causing running issues (flooding/too rich).
Good luck!

 

[oldboat1]

Use a piece of weed whacker line to clear the tell tale.

Get a buddy to steer the boat while you disconnect the controls at the motor. Check to insure the throttle opens fully, and the shift function works properly. Reattach cables to match motor settings. If the motor will not fully throttle up after cables replaced, suspect control box or cables. When your back there, check the temp at the top of the head — should be able to touch for a few seconds. Too hot to touch is too hot.

Can do this solo using a barrel (large plastic trash can works — water level about half way up the leg). Limit to high idle, except for short bursts to test. Keep the hose running and the water level up.

 

[FixOrDie]

The flywheel key and timing is something that I haven't checked. I used 100# test mono to check the tell tell for clear.
My guess is when it ran backwards, maybe the wings in the impeller flipped because it was peeing great. That is pretty simple to fix. My main concern is why they are telling me I need to rebuild the top end when I have 130 psi in both cylinders. I have never heard of cylinders bleeding down over time and that being a reason to rebuild. Ant thoughts?

 

[boobie]

IMHO the cylinder leak down test is only good for a four stroke motor where you have valves and such. A compression test is the best for a two stroke and with the compression you have you should be okay.

 

[Keyboardman]

130 compression sounds fine to me.

 

[wingster51]

The drive shaft and impeller turn the same way in forward,neutral,and reverse. The direction the propeller turns is done in the lower gearcase.