Johnson V4 Identification

[ThatDude114]

Hey guys, I just picked up a '77 16' Seaswirl and it has a Johnson V4 on it with no HP markers. I'm unable to find the transom tag for the motor or even where it originally was. I was hoping you guys could help me identify the year and HP. Thanks in advance.

 

[racerone]

My guess is 92 / 93 model year.----90 or 115 HP ----Post some more pictures or post number found on high speed jet in the carburetor.

 

[ThatDude114]

Really?! That's crazy, I was figuring it was mid 70's. I got the boat for free! So if it's a '92 that would mean its a Loopcharged motor with VRO correct? Did all these motors have VRO? It's most likely just a good idea to disconnect the VRO right? How do you go about that? Just ordered a Seloc manual for the motor to learn more about it. It's a far cry from the '68 Evinrude 55hp I have on my other boat. Also, where would the model plate be located on this motor? I can't find an obvious place they would have put it on the transom bracket. Thanks again for all the help!

 

[racerone]

No it DOES NOT mean it is a loop charged motor at all.-----They made the crossflow till 98 model year.----I am quite sure it is a 90 or 115 model.----Post more pictures !!

 

[ThatDude114]

Alright here's some more pictures.

 

[ThatDude114]

Is there anything in particular on the motor that I could take a picture of that would help?

 

[racerone]

That is NOT A LOOPER.------It is a 90 hp crossflow motor.----Do a compression test before you spend a penny on it.----Hopefully the plug wires are " solid wire core " type and not automotive wires.

 

[ThatDude114]

I believe the plug wires are Sierra 18-8839-1 wires meant for this outboard. Okay so 92 or 93 90HP crossflow outboard. It seems like many people like these motors and parts are easy to come by for them. What's your opinion on them? [h=1][/h]

 

[racerone]

Lots of them break piston rings.----Report the numbers of a compression test.

 

[ThatDude114]

Just a quick update, compression test will have to wait until Thursday, one of the plugs broke when I was removing them so I've gotta wait until I can get some new plugs. These compression tests are done at operating temp with the throttle wide open, correct? I spun the motor cold with the compression tester and received 60 psi +/- 3 between all cylinders. A compression test at operating temp should yield higher results theoretically right?

 

[jimmbo]

No, the temp doesn't matter much. Those numbers are so low, it would be difficult for it to run. You might try a different compression gauge. The throttle opening makes little if any difference.

The engine looks like a mid 1990s model. It has the later transom bracket. It's not a 115 as it does not have the bubbleback exhaust cover.

 

[racerone]

Throttle position just does not matter !

 

[ThatDude114]

I'll give a new compression tester a go. In my eyes it'd be pretty weird to have every cylinder equally that low on compression. Throttle position does not affect compression test results and hot vs cold do not yield significant differences in compression numbers, got it. I very much appreciate the help

 

[glust]

even though you are cranking it over to check compression if you suspect that the water pump is still good make sure you have water running through it. If you compression test it without water plan on replacing the rubber water pump impeller

 

[ThatDude114]

The impeller will get replaced as preventative maintenance but yes I do crank with the ears on. I was able to buy a new compression tester today. These readings are engine cold, all plugs out.

Upper Left: 115 Upper Right: 110
Lower Left: 113 Lower Right: 107

They don't look too terrible in my opinion. Factory spec is 125 correct? I fired it up today for a second after the compression test and it seems to run smooth. From what I've read, part of the reason these engines break piston rings is due to carbon build up so I should probably due a decarb right? Whats the preferred method and what do you guys use for it, Seafoam? Is there any other preventative maintenance I should do other than decarb, spark plugs, gearcase oil, and water pump? The VRO has already been taken off but I plan on getting the correct premix pump for it.

As always I do appreciate the help