1987 Evinrude 28 spl engine problems

[Ephenj09]

Hey everyone. I am completely new to this forum but I am not un familar with working on mechanical things. My speciality is mostly in the motorcycle department but I have the common know how on how almost any engine works. Anyway heres whats up.

My dad has a 16 foot star craft with a 1987 28hp evinrude spl motor on it. The problem is when you give it full throttle it bogs out. Our simple fix while we were stuck out on the lake was to put our thumb over the carb and it would run. This is what lead me to believe that the carb was dirty. Upon dissassembling I was shocked to find out that the carb was completely clean, and became dissappointed that this was not the problem. I then proceded to check all of the other things like compression and spark. This is where I became slightly un-familiar with two stroke outboard motors. My compression tester consistently reads 110psi on top cylinder and 120 on the bottom, and the top plug is always wet when you pull it ouf after running for how ever long we run it for. Would the rectifier have anything to do with this or the cdi box? I also noticed there was a little black box with two fuel lines that ran to separate places on the engine it self and by moving that little red arm it caused the motor to rev up and poop out upon wide open throttle. Alright so enough rambleing.

So now that you got to here the jist of the complete mess heres the few questions that I want to get answered.

1. Rectifier what exactly is it doing for this motor? Is it just converting AC to DC with a one wave node? Or am I missing the boat on that one ironic haha.

2. What should the compression ratios be? Most two stroke motorcycle motors have between 150 and 195 psi that i have worked on.

3. Any other tell tale causes that people may have came across for there motor not to hit power band at wide open throttle and just bog out?

 

[UK Vintage]

Re: 1987 Evinrude 28 spl engine problems

Hello,

Got this problem on my Johnson seahorse 20hp, only goes to a certani rpm then bogs down. I'm pretty sure the cam on the magneto wasn't synced to the carb properly, bent linkage arm, haven't tested it under load yet but I'm confident it'll be ok now. I'm not familiar with your engine but if it's similar to mine I'd check that. Its normal to have more compression on bottom cylinder. Some of the guys here told me to check the fuel pump too, bypass it as a test and use primer bulb as a pump, didn't work for me though!

 

[tashasdaddy]

Re: 1987 Evinrude 28 spl engine problems

red handle solenoid is the primer,
Primer Solenoid
the primer replaced the old choke butterflies in the carborators, pushing in the key activates it, like the old choke plates, but injects fuel directly into the intake.
The red handle is used when your battery is dead, and you have to rope start. You move the handle 180 degrees.
Normal operating position is with the handle back over the body of the solenoid, like in the picture below.

in the bottom of the bowl is the high speed jet. could be partially clogged.
diagram http://shop2.evinrude.com/ext/index.aspx?s1=bf6ad09c53cead335fcfd8a6471c0f7f

check your spark, on the cylinder with wet plug, you may have to bring motor up to temp, as coil could be heating up and failing at that time, causing no spark there.

your compression is within range. i would do a decarb on the motor, after running right, to see if they will even out.

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

 

[Ephenj09]

Re: 1987 Evinrude 28 spl engine problems

Tashasdaddy and Uk thanks for the quick replys. This forum is great so much info on boat motors.

So here is the update, I found my dad another 1988 evinrude 28hp spl on craigslist for 500 bucks. He went and picked it up and it came with everything needed to transfer it over, which is cool since we have extra stuff now. Heres the bad part the rectifier, the red wire was cooked, which stinks since the previous owner said that it ran. From what i remember without this red wire hooked up it wont run. My dad ended up finding a rectifier for 44 bucks a town over from here and the guy he bought it from said he would throw my pop a 100 bucks back for any issues we will have. So later today I will continue the swap with this new motor and will have the other 28hp spl for parts.

I ran a search on here and found that another member said that the wireing for to the terminal block would be
2 red wires
2 yellow wires
2 yellow with blue stripe wires
2 yellow with gray stripe + 1 gray wires.
Not necessarily in that sequence.

Just wanted to make sure so i dont mess anything up.

thanks for all the help so far

and if your inside reading this go fishing later lol.