'59 Johnson V4s-10 Compression ?

[jpchandyman]

I have a 1959 Johnson V4s-10 "fat 50" I have got most of the bugs out and it is running smooth. But tends to foul plugs after 3-4 hours. I am running hard pulling skiers and tubers. Fuel mix 32:1 87 octane. I did a warm compression test: all cylenders read 89-90 psi. This seems pretty low, but my seloc manual does not give the spec. What should compression be? Is it time for a ring job? We have snow here now so this is the time for rebuild before the summer season.

 

[JB]

Re: '59 Johnson V4s-10 Compression ?

What plugs are you using, JP? You should be using Champion J4C (replaced the J4J) gapped at .030".<br /><br />Fuel mix should be 24:1, like all pre-1964 OMC outboards.<br /><br />Your compression is fine. The important part is that they are all within 15%.

 

[R.Johnson]

Re: '59 Johnson V4s-10 Compression ?

Unless you know the RPM's on that engine, it would be hard to say where the problem is. Proping that engine could be a problem as there won't be much of a selection. 90 lbs. sounds pretty good, but I really can't say. It's been awhile since I worked with one of those.

 

[MCM]

Re: '59 Johnson V4s-10 Compression ?

Just a side note to what JB has said, the V4S-10 is a 1958 motor.<br /><br />Also in your post of August/05 you mentioned the motor was cutting out and the pressence of fuel on the water.<br /><br /> http://forums.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=28;t=035658;p=1#000000 <br /><br />Did you replace the coils? Have you done a spark test? Poor or insufficient spark coud result in fouled plugs, unburned fuel coming from the exhaust into the water and and overall poor performance.<br /><br />Also I noticed nobody responded to your previous post so Welcome to the forum

 

[Joe Reeves]

Re: '59 Johnson V4s-10 Compression ?

That engine as per a old OMC bulletin will run quite well with the 50/1 fuel/oil mixture. All of the bearings in that powerhead are either roller, ball, or needle bearings which is the main requirement to using the 50/1 mixture.<br /><br />Changing the mixture as above is going to make a difference.<br /><br />Also, in addition to JB's reply pertaining to the Champion J4C plugs. Some of the older engines, even though the J4C is the original recommended spark plug, just won't run properly with the J4C, some at low rpm, others at a higher rpm.<br /><br />OMC's recommended alternative spark plug in such cases is the Champion J6C which is slightly higher, but do no exceed the J6C rating. Bottom line.... change the mixture and try the J6C plug.

 

[R.Johnson]

Re: '59 Johnson V4s-10 Compression ?

Joe: Every time I mention 50:1 in an all roller, and needle bearing engine, I get in trouble. What's the number on that bulletin, I can't find mine.

 

[Joe Reeves]

Re: '59 Johnson V4s-10 Compression ?

RJ..... I have no idea of the bulletin's number. I know that I have it somewhere and recall reading what I stated above. Shoulld I ever come across it again, I will scan and list it.<br /><br />Right at the moment I'm trying to get over a heart problem that popped up last Thursday, so I really don't feel like digging that bulletin out right now. Trust me, it exists.<br /><br />The main requirement is that ALL bearing be either needle, roller, or ball bearings.<br /><br />Some engines have all of these EXCEPTING either the wrist pin bearing or the center main bearing, or both. Obviously these engines should not use the 50/1 mixture.

 

[R.Johnson]

Re: '59 Johnson V4s-10 Compression ?

Joe: I know every thing you say is correct, but I get in trouble every time I mention those pre-63,64 engines. I know what you mean about health, who came up with those ( GOLDEN YEARS )?

 

[jpchandyman]

Re: '59 Johnson V4s-10 Compression ?

Hey guys I really appreciate the imput.. I have been experimenting with both styles on the plugs, better on the J6's. The cuttout problem turned out to be a bad water pump. Center was torn so it pumped enough at Idle, but was slipping at high speed and overheating me. I also got improvement on the excess oil and fouling plugs when I went from 24:1 to 32:1. 50:1 sounds a bit extreme on that old motor. I have picked up several props on ebay, and have done some experimenting with them. One pulls my tubers a bit faster, but won't get the skiers out of the water. The smaller prop gets up the skiers but feels a bit slow. Sound like I should leave well enough alone on the pistons. My dad used to say "if it ain't broke don't fix it".

 

[jpchandyman]

Re: '59 Johnson V4s-10 Compression ?

Joe: I just checked the parts catalog and all of those bearings are rollers, includeing the ones on the wrist pins. I am planning to hook up a tack and temp guage for the summer. When playing with props what is the ideal rpms I should be looking for?

 

[MCM]

Re: '59 Johnson V4s-10 Compression ?

Actually I like "if it aint broke don't break it" just my own twist on it but it keeps the costs down.

 

[MCM]

Re: '59 Johnson V4s-10 Compression ?

Joe, not to hijack this post but I'm sure I'm not the only one here on the forum that hopes for a speedy full recovery and that you're feeling better soon

 

[Joe Reeves]

Re: '59 Johnson V4s-10 Compression ?

JP..... The alarm is set right now so I can't get at my books but if memory serves me correctly, the top rated WOT rpm on the 1958 1nd 1959 50hp Evinrude/Johnson is 4800 rpm.<br /><br />MCM... Thank you, I appreciate your thoughts.