Evinrude 140hp Rebuild? Low compression.

[slimpickens]

I am looking at a boat with 140hp evirude tha i believe to be about a mid to late 80s v4 its on an 85 boat and the color is silvery with the navy stripe with lettering. I forgot to get the serial# when i checked it out. The motors compression seemed low about 70-80lbs on all 4 with all 4 plugs out. I found what looks like the old mercury oil mixing unit still in use. I am not savvy with outboards or evinrudes i just got my first last year and it was a mercury and had the same compression #s and the oil injection unit appeared to have contributed to the low #s. Did the evinrude come with a similar premix unit and are the #s too low to be useable? If i have to rebuild how difficult would it be? Can anybody compare the difficulty of rebuilding this engine to a small block chevy of which i am very familiar? Sorry for being so long winded.

 

[HighTrim]

Re: Evinrude 140hp Rebuild? Low compression.

The system you saw is called a VRO unit, or Variable Ratio Oiling System.

Some reading if you are interested.

"http://continuouswave.com/whaler/reference/VRO.html"

The compression numbers are low, but the main thing is that they are equal. You will get different reading depending on the gauge, engine temp, etc...

 

[slimpickens]

Re: Evinrude 140hp Rebuild? Low compression.

Thanks for the interesting reading that explains alot about the system. I am not sure that the system wasnt a merc. unit however if it is a omc then i feel better about using it after a checkout. Would a rebuild be difficult or is it straight forward are there any things to be really carefull of on this motor or tricky parts or areas to be mindful of?

 

[ezeke]

Re: Evinrude 140hp Rebuild? Low compression.

During the 1980's the 140 HP engines go from the crossflow to the looper and then to the big bore looper. As you saw, the oiling systems change a lot. By 1993, the VRO systems are replaced on new engines by OMS systems and many of the VRO systems were replaced at that time or later by OMS upgrade systems as well.

Check the engine again for the model number. The loopers have the number on a welch plug centered near the top between the cylinder banks. The best of the old VRO systems were VRO2 units and the tag with that title may still be on the pump.

I'm still using the VRO2 pump on my 1988 140, but I use it as a premix pump. The thing won't die, and I have no plan to replace it until it does.

 

[wavrider]

Re: Evinrude 140hp Rebuild? Low compression.

Do a good de-carb and the compression numbers will most likely increase.

I have had then increase as much as 30 lbs after a de-carb.

Use pre-mix with sea foam in the pre-mix, I run the engine until warm, normal operating temp, then shut it off, pull plugs and spray all cylinders with deep creep, saturate them real well, using the nozzle od plastic straw to really concentrate on rings. Re-install plugs hand tight.

Let sit at least 15 minutes. Remove plugs and turn engine over few times. this blows all the big chunks of carbon out and gets rid of the excess deep creep so as not to foulf plugs to much.

Install plugs and run the engine. It will smoke like a banshee on fire and after the smoke clears check your compression again.

 

[fishmen111]

Re: Evinrude 140hp Rebuild? Low compression.

Slim,
I am new to this forum and new to outboards in general, but listen to the guys on here, they know their stuff. In regards to simplicity compared to a SBC, I just tore down my first (only a 2 cyl.), and was amazed at how simple it was. I spent way more time fighting frozen bolts than actual dis-assembly. There are very few internal parts. I am waiting for parts to start the rebuild. You must have a OEM manual to work on these. One thing I noticed, is the tolerances are much much tighter, and you need to measure and remeasure dimensions. You still measure taper, oor, bore, journals etc. just like any other motor, they just need to be dead on to handle the constant high rpms. No mechanic here...just my novice observation.

 

[slimpickens]

Re: Evinrude 140hp Rebuild? Low compression.

hanks for all the great input I wont be able to get the #s unless i go and buy the boat it is on but that is going to happen it looks like. I appreciate the input on the buildup as i havent ever been into a two stroke except for a weedeater. I bout the manual for the merc i bought last year but it ran ok with 75psi so i let it go and am gonna sell it for the evinrude power as after looking at the parts and other pluses of having a evinrude or johnson I found out that the cost and better failure record are on my side with them. I am gonna try the decarb with it when i get it i did one on the merc using some onan decarb aresol and boy did it stink and smoke! I like the seafoam smell so i hope its not as bad. I will surely read anymore responses and will post a new topic on it again after ive had a chance to get the motor and clean it out and retest but form what i hear and have read it should run with 75 or so psi just not like it should. So ill hold off on a rebuild.

 

[slimpickens]

Re: Evinrude 140hp Rebuild? Low compression.

Sorry for the typos my little device isnt very keyboard friendly. THANKS AGAIN FOR ALL THE HELP. FEEL FREE TO SHOOT ANY AUTOMOTIVE ?S MY WAY I AM ASE CERTED MASTER IN AUTO AND HEAVY TRUCK SO MAYBE I CAN HELP YOU ON SOMETHING SOMETIME. PM ME. THANKS AGAIN. I just like asking someone more familliar than I on the subject before spending the cash to try to figure it out.

 

[G DANE]

Re: Evinrude 140hp Rebuild? Low compression.

Have you tried another gauge. Having heard you found genrally low compression on all cylinders, both on this one and your Merc makes me a little suspicious about your gauge, Low compression on all and even is a rare thing. Those things rarely wear out, something usually happens to a cylinder or two, due to dirty carbs or whatever. Some newer motors will have compression around 95-100, but i think that was later vintages.I wouldnt just jump to a rebuild without investigating further.

 

[Benny1963]

Re: Evinrude 140hp Rebuild? Low compression.

hey slim i have found several power heads on ebay used thru time that had good comp numbers try a decarb and look for a used powerhead
in your area to beat the shipping, if ya lived close i could get you a 115 with power trim cheap cheap with some good comp numbers120 115 120 120 115 dry.
good kuck bennyb

 

[slimpickens]

Re: Evinrude 140hp Rebuild? Low compression.

I tried two different gauges on my merc and both were within 5 psi and then i checked them both with a set that are calibrated we use to set the gauges on the fire pumpers so i guess they are within about 8 % at 100psi to the calibrated gauges thats what i found about 8 months ago. Im in northeast texas if your not too far and the price is right i might be intersted in a good powerhead thanks. PM me with the details on it and the location.

 

[ezeke]

Re: Evinrude 140hp Rebuild? Low compression.

You should be aware of the difference in the way horsepower was rated before 1985. The 115HP from 1984 back is actually around 90HP by comparison to what is rated 115HP now, The big bore loopers in 1988 and 1989 not only had the true 140HP but had tremendous torque. Those engines will leave the old 140 crossflows, which are more like 115HP, in the dust, or spray as the case may be.

 

[slimpickens]

Re: Evinrude 140hp Rebuild? Low compression.

Thanks for the heads up on the ratings I believe this is an 85-87 motor as the color and graphics are the same as an 85 my uncle had. When I buy it and decarb it ill make sure. As for power and speed I get enough of that during my 2 1/2 hours of commuting to work everyday. So my fishing time is not so hurried unless im pressed for time during the Mcdonalds big bass tourneys that is but thats what the friends new H.O. tourney rig is for "right"
I appreciate it though. Im just rying to get the most for less you know what I mean. If 75-80 psi gets me around for a year or two and i sell it to fund the bigger one OK by me. I just wanna get the info before i buy it. Thanks again all Ill be back im sure for this or other topics.