One Step Closer - 25 hp 1975 Evinrude

[Jmcever]

Started a new post since the last one was getting so long - let me know if this was the not the right thing to do.<br /><br />Made a spark plug gap tester like BoatBouy suggested – got good spark on both. I still think I have some leakage from the # 2 coil – get shocked when I touch the rubber boot/wire.<br /><br />I noticed that the plate that the points mount to (also cams the throttle) rotates clockwise about 5 to 10 degrees when I pull on the cord. I held the plate stationary so it couldn’t rotate, squirted some fuel mix down the throat of the carb and it started right up. <br /><br />I was hoping to get a manual but stores are closed until after the first – think I’ll order on line.<br /><br />Three questions:<br />1 – Should the plate be rotating as I pull on the cord? <br />2 – What is a good manual to order? Iboat.com has a Seloc Tune up and Repair Manual for $36.95<br />3 – I’ve got pictures but don’t know how to post – Can anyone point me to the instructions on how to include a picture in the posting?<br /><br />Thanks for all the help,<br />JMc24

 

[alden135]

Re: One Step Closer - 25 hp 1975 Evinrude

What I can help you with:<br /><br />It's better to maintain the same thread so folks can keep track.<br /><br />Buy a factory service manual. I buy from marineengine.com, there are others.<br /><br />Use the "full reply form". there is an image tag. Your pics need to be hosted by a site like photobucket.com. After uploading them you copy the address into the box that appears after clicking the "image" tag on the iboats full reply form.<br /><br />Someone else will help with the motor problems. I'm still learning.

 

[Paul Moir]

Re: One Step Closer - 25 hp 1975 Evinrude

alden is dead on about the manual. The factory one is much better. If you're unclear about anything in it (say, some basic service point) you can just ask here. I checked ebay for a '75 manual but there doesn't seem to be much. There's a bunch of ignition system changes around that time, so it's probably best you make sure you get a '75. ('74 were abundant unfortunately!)<br /><br />The plate should not rotate when you turn the cord. It's supposed to be controlled exclusively by the throttle. There are magnets inside the flywheel that act on charge coils on top of the plate, which will induce it to move. But really the linkage should have enough resistance to overcome that. If the plate is excessively wobbly, the coils can actually come in contact with the magnets in the flywheel. It will be very noisy when it runs when that happens though.

 

[R.Johnson]

Re: One Step Closer - 25 hp 1975 Evinrude

There is a machined surface at the top of the engine block that the ignition armature plate pivot's on. There is also a brass inner ring on the armature plate. These two mating surface's can, with time,wear loose. When this happen's, it will let the armature plate rock up, and down, and somewhat, side, to side. This can let the flywheel magnet's drag on the coil heel's, dragging the plate around as the flywheel rotate's. This can also cause erratic point timing. Joe Reeves has a post on how to correct this problem, by careful peening of the inner brass ring with a sharp punch to tighten the fit. You will also want to check that the coil heel's do not extend beyond there seat's of the armature plate. This will reduce the air gap, letting the coil's to be struck by the rotating flywheel.

 

[Jmcever]

Re: One Step Closer - 25 hp 1975 Evinrude

Here are a couple of photos. Two show the position of the armature before and after pulling. The third is a picture of my spark plugs after decarbing with SeaFoam. The dirty plug is the cylinder that has low compression (70 psi). Should I re-do the decarb?<br /><br />Any comments?<br /><br />Hope I did the images right.<br /><br />

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[R.Johnson]

Re: One Step Closer - 25 hp 1975 Evinrude

Remove the cylinder head, and look.

 

[Paul Moir]

Re: One Step Closer - 25 hp 1975 Evinrude

If R.Johnson doesn't mind, I'll ask you to humor me a second. On your engine I think the fuel pump is on the bottom bypass cover. If the dirty/low compression plug is from the bottom cylinder, then you could have a leaking fuel pump. The test is simple - unbolt the fuel pump from the bypass cover, and pump up the primer bulb. If fuel comes out the back of the fuel pump, the diaphram has ruptured.<br /><br />Just thinking that perhaps the low compression is the result of an over-rich condition on that cylinder. That can lead to one or two piston rings stuck in the ring grooves from coke & carbon which will lower compression. If so, decarbing may restore your compression.

 

[R.Johnson]

Re: One Step Closer - 25 hp 1975 Evinrude

Paul: I would certainly agree that an engine that age could have a fuel pump problem. What I don't understand is, why the reluctance to remove the cylinder head when you know the engine has low compression on one cylinder. I won't go after an ignition, or fuel problem on an engine I know is probably damaged. In my experience, if an engine has been run for any length of time with stuck piston rings, that piston, cylinder wall, or both are going to be scuffed. Nothing in a can is going to take that away. I know I can take this 25 HP engine, and make it run, but you are not going to be very happy with the way it runs. I can't tell someone there engine has one bad cylinder, but I went ahead and done the carb., and ignition anyway. When I come across an engine with low compression, I remove the cylinder head, or stop right there. Not pulling the cylinder head is like saying, If we don't talk about it, maybe it will go away.

 

[ramirez62]

Re: One Step Closer - 25 hp 1975 Evinrude

If you don't mind me asking JMc, how the hell do you keep you engine so damn clean? I got a '79 and she's dirtier thant smut. Any tips?

 

[Jmcever]

Re: One Step Closer - 25 hp 1975 Evinrude

I've ordered an OEM manual online so this may be the last of "its in the manual questions". There is a white plastic piece that mounts to the engine block on the back left hand side. Its spring loaded and looks like it should engage the starter fly wheel (?) to prevent starting in gear. Mine is spring loaded so that it does not engage. Before changing I thought I'd ask.<br /><br />The armature plate (for the points) has a bit of wobble and some side to side movement (I'll do a search for Joe Reeves posting). The plate rotate clockwise (retards timing) about 3/4" when I try to start. If I hold the plate stationary it starts on first pull. <br /><br />Paul - The low compression cylinder is on top (#1). The fuel pump diaphram is okay.<br /><br />R. Johnson - Unless things change I'll probably take the cylinder head off. I'll wait for my manual to arrive. I'll let you know outcome.<br /><br />Hoss - I hate working on dirty engines. Tooth brush and degreaser.

 

[MCM]

Re: One Step Closer - 25 hp 1975 Evinrude

Hi J Mc24, Two helpfull sites that have diagrams and parts lists for your motor are this one, BRP SITE, sometimes it doesn't always work. There's also iShopMarine.com, click on parts lists and locate your motor, the diagrams and parts info comes in very handy when working on these motors. The same info can be found in the OEM parts catalog.<br /><br />Hope this will help some

 

[Paul Moir]

Re: One Step Closer - 25 hp 1975 Evinrude

R.Johnson: Its a moot point now but I thought I should explain myself about the reluctance to remove the head. For you and me it's a simple task where we would pop it off, check for damage, check the head for flatness (surface if necessary) and torque it back on. I think though that some of the people that find their way here don't really have the proper tools for the job. Most notably the torque wrench. And you know what those cheap torque wrenches they're likely to buy for the job are like! Worse than none at all.<br />But I have to admit, 20psi surely is in the outer limits for something you can recover. <br /><br />J Mc24, I hope you don't mind that aside in your thread. Thanks for your patience.

 

[R.Johnson]

Re: One Step Closer - 25 hp 1975 Evinrude

Paul: I want to point out that I am in agreement with you, and that your post's are alway's on solid ground. I certainly agree on the torgue wrench! On these a aluminum engine's, the in/lb torgue wrench is the one to use. About the only place for the ft/lb is on the flywheel. I use a 500 in/lb Snap-On torgueometer on everything, and a breaker type ft/lb on flywheels. The old torsion type wrench's are OK, but you want to have both.

 

[BoatBuoy]

Re: One Step Closer - 25 hp 1975 Evinrude

Now that you've brought it up, I had an interesting conversation last night with a friend of mine who wrenchs engines on KC-135 refueling tankers. I learned that the old torsion type you mention never need re-calibration under ordinary use. <br /><br />The breaker type have to be sent to Shaw AFB for re-calibration anytime they hit the floor. Also every AM they go through a routine w/breaker type. On a nut welded to workbench, they take them to 20% of their range, then 50% of their range, then 80% of their range. Then they step back down the same way. That routine's not necessary w/torsion (beam) type.

 

[R.Johnson]

Re: One Step Closer - 25 hp 1975 Evinrude

BoatBuoy: I have thought about that also. I would think that the only way to damage, or take a torsion type wrench out of calibration would be to over extend it, such as trying to use it as a regular wrench, or breaker bar. The breaker, or dial type do have to be checked. I don't know if a calibration shop would repair the wrench, they would probably just tell you how much it was off. It would be interesting to send my Snap-On back to the factory, just to see what they would tell me. Any way! It would be a good test of their lifetime warranty.

 

[G DANE]

Re: One Step Closer - 25 hp 1975 Evinrude

I've experienced one situation where the torsion type is far over the breaker types. It allows you to see how far from the decided torque you are, while applying torque, which I think is essential when working with older threads in aluminium. I actually feel how the threads and bolt take the torque, the way up.

 

[G DANE]

Re: One Step Closer - 25 hp 1975 Evinrude

I've experienced one situation where the torsion type is far over the breaker types. It allows you to see how far from the decided torque you are, while applying torque, which I think is essential when working with older threads in aluminium. I actually feel how the threads and bolt take the torque, the way up.

 

[reka12]

Re: One Step Closer - 25 hp 1975 Evinrude

J MC24: Please use a good torque wrench. While putting the head back on my '70 25hp Rude, I used a cheapy and did irreprairable damage to the block. I now have garage art that will never move again. Its a shame. New starter, carb and everything else is clean and in good condition. Mike

 

[Jmcever]

Re: One Step Closer - 25 hp 1975 Evinrude

Thought I'd post an update. Took the boat out this past weekend. I still need to adjust the low/high speed setting. I also have to hold the armature plate from rotating when I start. After I start it up it seems okay. When I got home I checked the compression. Number 1 (upper) is now 80 psi and number two is 90 psi. Spark plugs both looked good. I plan to take it out one more time before taking the cylinder head off.<br /><br />Thanks for all the comments. I'll be sure to use a good torque wrench. What type of lubricant should I use on the threads? I would think this would be equally as important as an accurate torque reading.<br /><br />Thanks again,<br />JMc

 

[BoatBuoy]

Re: One Step Closer - 25 hp 1975 Evinrude

I think torque specs are for clean, dry threads.