Evinrude 25hp Compression

[Redmen]

I Have A 1997 25hp Evinrude, 3 Cylinder, Electric Start, Oil Injected Outboard. Upon A Compression Check The Cylinders Were Showing Between 90-95 Psi. Is This The Correct Compression For These Cylinders Or Is It Too Low? Thanks.

 

[JB]

Re: Evinrude 25hp Compression

That is fine, Redmen. There is no published minimum. What matters is that they are close (10%) to each other.

 

[Redmen]

Re: Evinrude 25hp Compression

I Am Trading The Motor In And The Dealer Wants To Discount My Trade In From $1,500 To $1,000 Because He Says The Compression Should Be Up Around 115 Psi. Do You Think This Is Reasonable?

 

[tx1961whaler]

Re: Evinrude 25hp Compression

I think he is trying to bargain you down by using any excuse he can think of. It's an age-old game. But he can do that, unless you're prepared to say "sorry, no deal" and walk out the door. About 70 percent of the time they catch you before you can get out, or you have a phone call waiting for you when you get home.

 

[kissmywake]

Re: Evinrude 25hp Compression

Compression pressures can vary from motor to motor depending on the static compression ratio. Compression only tests a small amount of the cylinder with absolute certainty and the rest can be damaged. Have the dealer perform a leakdown test, this can tell you the actual condition of the engine. I have seen engines with perfect compression, but had cylinder damage to the lower end of the cyl. If they refuse to do this, or argue with you, then go to a real shop and stop wasting your time with underqualified rednecks.

 

[Redmen]

Re: Evinrude 25hp Compression

When you say 70% of the time, you mean they back down if you walk out the door or call you later at home after you've walked out? This is the problem with buying a motor at a boat show. You put down a deposit and the dealer orders the motor. If the deal doesn't go through, they will keep your deposit as a "restocking charge" for sending the motor back. So I think either way you've(I've) lost.

 

[jbjennings]

Re: Evinrude 25hp Compression

Well, here's my opinion, for what it's worth, which is probably very little:

Although there's no published compression numbers, any mechanic that's familiar with that engine is going to have a pretty good idea of what compression to expect for it. If a motor has quite a bit lower compression than what one normally sees, then it's reasonable to suspect that the low compression motor may have a lot of wear, or some kind of problem, especially in an oil injected motor (I would think). Otherwise, why would anyone want to know what the compression was? Sure, everyone looks for the obvious difference in compression that shows up when a really bad problem arises, but I personally look to see if the compression shows to be what I expect or not. If it's not as high as what I expect, I'm passing on that engine.
When that dealer offers your motor for sale, he's most likely going to get the "what's the compression" question. When he says "95 psi on all 3", being truthful, what's a buyer to think? If they're informed as to what the compression should be, and it is actually 115psi like the dealer says, they're probably not going to be interested in that motor.
I've seen the recommendation of "anything over 100psi and within 10% of each other is good" many times on this site for a motor that size. But, when the dealer expects the same, somehow they are wrong to offer a lower price???? I don't think that's fair. It might be that the dealer really doesn't even want the engine with that level of comrpession, and is trying to be fair with the seller even accepting it on trade. Then again, I'd be wanting to see that compression test in person, and the test done again on a different motor to verify the gauge was correct, since they are notorious for being inaccurate.
Just food for thought----I'm neither a qualified mechanic or otherwise, but I do pay attention to what reliable folks tell me and what I see on my own engines, which I have several of. My '99 30 hp OMC 2-cylinder has 125psi on both cylinders and runs great. I've never tested a 3-cylinder 25hp so I have no idea what to expect. The 3-cylinder motor may be a low compression motor for all I know!
I'm just saying that if it has 20psi lower compression than the normal 3-cylinder 25hp OMC they test, then they do have a "leg to stand on" in offering you a lower price for yours, whether your motor is really "bad" or not.
Just an opinion,
JBJ

BTW, why not just sell the motor yourself and get what you think it's worth? That's what I do when I buy a new car-----the dealer never gives you what it's really worth--they plan on making a tidy profit on it.

 

[Redmen]

Re: Evinrude 25hp Compression

Thanks. He said he has another 25 HP Evinrude motor there that has compression of 115. Also, based on the market, it isn't worth me trying to sell the motor. Considering the traffic that comes through his store, he'll have an easier time they I would in selling it.

 

[tashasdaddy]

Re: Evinrude 25hp Compression

"restocking charge" is this in the contract you signed. did it state value of trade in??

take the motor home and do a decarb. that is what the dealer is going to do.

Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.

afterwards compression.recheck

then take it back to trade. really i have never had any luck, doing a trade in on an outboard.

 

[alangf]

Re: Evinrude 25hp Compression

Another thing to consider is that you can get considerable difference in compression tests by using a different compression tester. There is also a fair amount of technique involved. Doing a decarbon is great advice. After doing that redo the compression test. If the figures are still a bit low (the engine will run fairly well with 80 pounds) pour about a teaspoon of oil in the cylinder and recheck. This is called a wet compression test. The oil will temporary help worn piston rings to seal. If the reading comes up more than 5 to 10 psi the rings are worn.

 

[Redmen]

Re: Evinrude 25hp Compression

What if after the "wet test" the compression only comes up 10 psi? Does this mean it needs new rings?