Compression too high?

[tkdrumr]

I'm looking at a '97 E70TLE powerhead to replace my failed '01 J70PLSIS powerhead. My concern is their purported compression is 155 on all three cylinders. Is that high for a used PH? I don't have the compression specs for that PH but most info I've found seems to put good compression at about 120. Could this be carbon buildup, or worse yet, a bad rebuild with the bore too tight for the piston? The PH looks clean, almost too clean for a used PH. Should I pass this one by? It's >1000 miles from me so no chance to inspect.

 

[Scott Danforth]

could just be a crap gauge

 

[Chris1956]

Could also be hype from the seller. Bigger compression numbers make for better sales. The important thing is that the compression is even. If so, the powerhead is likely good, mechanically.

Thake a look at the splines on the crank. Stripped is bad. Check the top main bearing by wiggling the flywheel. It is not a precise check, but if you can make it wobble, the bearing is definitely bad, and maybe others are as well. Obviously turn the flywheel by hand and feel for tight spots.

 

[tphoyt]

I would be skeptical. Unless it’s a really great price that won’t hurt if it’s not up to par I would hold out for something you can put your hands on.
Just me of course I don’t trust anyone any more.
Best

 

[Crosbyman]

bring your own known good meter and if not 155 bargain his price down for not being full honest

 

[tkdrumr]

I would be skeptical. Unless it’s a really great price that won’t hurt if it’s not up to par I would hold out for something you can put your hands on.
Just me of course I don’t trust anyone any more.
Best

That's my thought, skeptical ... it's a fair price, $1K shipped from Fl. Cheaper than most used complete outboards with this PH. The seller appears to be an outboard service business. Priced as-is but since he put it out there as 155 even compression it can be considered a guarantee.

Could be hype, could be a bad gauge, could be other problems. I'm probably going to pass on it for several of these reasons. But to satisfy my curiosity ... if we assume 155 is accurate, does that sound too high?

 

[Crosbyman]

comp aside a 1000 miles is a 1000 miles if anything goes South.
have you searched the local market to compare.

 

[racerone]

Rebuild the one you have.----Not hard to do unless it is a " salty " motor.

 

[tkdrumr]

Rebuild the one you have.----Not hard to do unless it is a " salty " motor.

I've considered this. The PH isn't salty but it had evidence of overheating. Maybe the VRO failed and it ran oil-starved. One of the crank journals is worn down, that piston was cracked, the cylinders unsurprisingly scored. When I started adding up costs a used PH in good condition sounded like an easier/cheaper option. Used crank $200. Block machining est. $100/cylinder. Rebuild kit almost $600. Unless you think my estimates are off. I didn't measure the bores but the comp #s were around 98-95-70 (if I remember correctly) so I'm assuming oversizing is necessary.

I put a '73 Evinrude 65 hp Triumph on this boat and it runs pretty well. But with the J70 above my wife and daughters could get in the boat, tilt the motor down, and start it up while I parked the truck. The Triumph is a little needier with the butterfly choke and no power trim. Not to mention the selectric shift takes a little finesse.

 

[tkdrumr]

comp aside a 1000 miles is a 1000 miles if anything goes South.
have you searched the local market to compare.

Yeah, missed a couple decent deals. Most J70 motors are around $2000 - $2500 in this generation. There's one or two guys locally that seem to buy up the decent used OBs to resell. I've seen some parts OBs for about $1200-$1800 but those are around 3-5 hours away. I'm not in a hurry, I've got a motor that's working for now. I'll probably pass on this one and keep my eyes open locally.

 

[Chris1956]

Iboats has some powerhead rebuilders. You might check prices on their rebuilds. IME they go thru them pretty good, so you don't have bad blocks.

 

[racerone]

There can not be electric shift on a 1973 model Evinrude.

 

[tkdrumr]

There can not be electric shift on a 1973 model Evinrude.

Sorry, my bad. '72 Rude on a '74 Starcraft Supersport 16'.

 

[saltchuckmatt]

Never buy a used outboard from Florida....at least in general.

Super salty and ran all year.

Best state? Like Michigan, fresh water and boating season is short.

 

[saltchuckmatt]

By the way, where are you located?

 

[tkdrumr]

By the way, where are you located?

Syracuse NY ... also a very short boating season.

I've pretty much decided on skipping this one .... but does anyone have a comment as to compression? How much is too much?

 

[racerone]

Overthinking on the compression on this motor.----Normally it would be about 120 / 130 on that motor.-----You have an optimistic seller.----Or a seller with a poorly calibrated gauge.

 

[saltchuckmatt]

Yes I agree, got outboard motor probably left the factory at about 140 tops just kind of leads to the fact that the guy doesn't know what he's talking about or has the bad gauge, either way he doesn't know what he's talking about.

The reason why I asked you where you were is because I was going to point you in the right direction as to where to get one. Now I'm on the west coast so I don't know your area very well at all but I bought parts from this source and he's not that far from you, best of luck to you.

timsoutboard.com

 

[tphoyt]

There you have it. I didn’t want to say it a get scolded. My skepticism is the advertised numbers are high and the seller would know this if they knew what they had. If I found numbers like that I would be looking to try another gauge to confirm and make an honest statement.

 

[tphoyt]

Your right Matt I have heard good things about Timsoutboards. I think they are in NJ