1996 Evin 15 hp 2 cy. Bogs down "ONLY" in the forward position.

[AIMLOWR]

It's a newer engine for me and I'm new to boating. It was working fine then it just started to bog down while I tried to open it up. It might even sputter (one in a great while). Kinda like it finally got some gas and then back to being stuck in a mid-range rpm max. I can get around but not fast. (CAN'T REACH HIGHER RPM'S IN FORWARD)
I know you are thinking, fuel, fuel line, fuel pump, carburetor, plugs... I replaced or rebuilt all of those items and even added a new tank.
So I did all of that work and it's still doing the same thing.
I can easily keep it at full throttle in neutral and reverse ...... (That seems important?)
Literally just tested it again and found that it powers forward at max rpm" IN A GARBAGE CAN" can filled with water but it will not go to full throttle to push my boat on the ocean.
Obviously, it takes on a bigger load going forward, so what might restrict its RPM's????
Also, likes to start with full throttle??
Changed gear oil just before the problems...

Oh, I forgot to mention that I'm pushing a 42' pleasurecraft. Not really, 15' Jon boat.

Pic of model #

 

[racerone]

Mixing gas and oil at 50:1 ?------What pitch is the propeller ?

 

[racerone]

Post compression test values here.----And does spark jump a gap of 3/8" or more on both leads ?

 

[AIMLOWR]

Mixing gas and oil at 50:1 ?------What pitch is the propeller ?

Mixing gas and oil at 50:1 ?------What pitch is the propeller ?

I am mixing at 50:1
I don't know the pitch, Is there a number on the prop, if not, how would I find the pitch?
One thing to remember is that it was working fine for a few days. It was moving around with full power then it just started acting up.
I hope that helps, thanks

 

[racerone]

See post #3 and provide answers.----That will help you find a path forward.-----I can not see or touch your motor !

 

[AIMLOWR]

Post compression test values here.----And does spark jump a gap of 3/8" or more on both leads ?

I just ordered a compression tester, it should be here tonight. I put new plugs in and gapped them at 0.030 in as per my manual. Are you suggesting that I pull the plugs out and see if it will jump from my plugs to something else at least 3/8" I can check this out when I get home.

 

[racerone]

Your motor may be running on just 1 cylinder.----So some testing needs to be done and facts can be posted.----Other than that you can just keep guessing.---Sorry

 

[AIMLOWR]

Your motor may be running on just 1 cylinder.----So some testing needs to be done and facts can be posted.----Other than that you can just keep guessing.---Sorry

 

[AIMLOWR]

Hopefully my compression tester comes in today. I will post my results asap. Thanks

 

[Thirsty Endgrain]

I just ordered a compression tester, it should be here tonight. I put new plugs in and gapped them at 0.030 in as per my manual. Are you suggesting that I pull the plugs out and see if it will jump from my plugs to something else at least 3/8" I can check this out when I get home.

Look up spark gap tester.

 

[909]

First ... stop revving full throttle in neutral

It runs fine when in a barrel because there is no load. The reason why it bogs under load is because part of your engine is causing a lean environment and it's sucking pure air , when its supposed to suck air + fuel . It leans out and bogs / sputters / dies . When you pull the choke slightly , it momentarily corrects the balance with the supplementation of additional fuel, and appears to work normally for the moment. The most common reason is because your engine has overheated from lack of maintenance . Your gaskets are probably shot , and you lack pressure where it needs to be sealed to create that pressure. This would also explain the hard starting and why you need high throttle to start it. The environment is so lean you need to flood it to start.

 

[AIMLOWR]

Look up spark gap tester.

First ... stop revving full throttle in neutral

It runs fine when in a barrel because there is no load. The reason why it bogs under load is because part of your engine is causing a lean environment and it's sucking pure air , when its supposed to suck air + fuel . It leans out and bogs / sputters / dies . When you pull the choke slightly , it momentarily corrects the balance with the supplementation of additional fuel, and appears to work normally for the moment. The most common reason is because your engine has overheated from lack of maintenance . Your gaskets are probably shot , and you lack pressure where it needs to be sealed to create that pressure. This would also explain the hard starting and why you need high throttle to start it. The environment is so lean you need to flood it to start.

Wow! Thanks for all of the info. I'm going to explain some of tonight's testing results on another reply. Thanks

 

[AIMLOWR]

I just ordered a compression tester, it should be here tonight. I put new plugs in and gapped them at 0.030 in as per my manual. Are you suggesting that I pull the plugs out and see if it will jump from my plugs to something else at least 3/8" I can check this out when I get home.

I did a compression and spark plug test this evening. The compression only came in around 80-85. Although I don't have a ton of confidence in my compression tester. I used a loaner from O'reilly auto parts but I'm not sure how much I trust it. I pick up a new one tomorrow.
However, however, I could not register a spark on my top cylinder. I purchased a spark plug tester as suggested. It was literally running on my bottom plug/cylinder.
It was nice to see no spark because it's "probably" an easy fix, I'm really concerned about the compression, I hope the tester was off. I'll pick up some new spark plug wires and redo the compression test tomorrow evening,
Thanks, everyone for the suggestions, we'll see more results tomorrow.

 

[AIMLOWR]

Post compression test values here.----And does spark jump a gap of 3/8" or more on both leads ?

Bought a spark plug tester tool tonight, glad that I did, thanks. Missing spark on top plug..

 

[AIMLOWR]

Your motor may be running on just 1 cylinder.----So some testing needs to be done and facts can be posted.----Other than that you can just keep guessing.---Sorry

Please read my last reply as you are correct. Only one plug was working.. more results on top post reply

 

[Thirsty Endgrain]

Likely bad coil if you're not getting spark. Or bad connection. How does the ground wire look?

 

[AIMLOWR]

Likely bad coil if you're not getting spark. Or bad connection. How does the ground wire look?

I think it is my coil. I meticulously cleaned all of the connections and it still won't make a spark for the top plug. I'm going to look for a way to test it online.
I rechecked the compression with a new gauge, they both registered 91-92 ish.

 

[AIMLOWR]

Likely bad coil if you're not getting spark. Or bad connection. How does the ground wire look?

I cleaned everything up, but still no go.
I ordered a new ignition coil, new power pack, and new wires. I really hope that it solves my top spark issues.

 

[racerone]

Switch the 2 orange ( striped ) wires and post results of spark test.-----Orange / blue stripe is for top cylinder.

 

[AIMLOWR]

Switch the 2 orange ( striped ) wires and post results of spark test.-----Orange / blue stripe is for top cylinder.

I switched them, it would not start.
I have a new coil and power pack coming tomorrow. I'll try the coil first.
thanks