1988 150hp 2stroke evinrude --- Bogging

[mgusha16]

I had some jack *** mechanic rebuild my motor. Band new pistons, carb adjustment, gaskets... I've been running it at a 25:1 because of the engine break in period. It's been fouling plugs like no other. But also it seems like it's not getting the power it used since the first time I took it out. Yesterday I took out the boat. Cold started it with little to no issues, got up on plane right away and it was running fine. The when I slowed down to the no wake zone, it sounded like it wanted to die and when I gave it throttle it just bogged out and wanted to die. Then eventually after trying to mess with the RPMs when it was in gear it decided to die. The funny thing is that when the boat is in neutral I can give the boat full gas without any bogging problems at all. It's only when the boat is in gear. Then somehow after giving the boat high RPMs in neural and slamming it into gear it showed power and took some work but it eventually got up on plane and we made it back to the dock. But when we slowed down and got in the no wake zone it did the same bogging thing again. We also cleaned off the plugs with sand paper because it was having a starting problem. But what do you guys think is going on? Is the fuel VRO not working properly or could it be the 25:1 mix? Or both? Please let me know your thoughts.

 

[Barnacle_Bill]

Re: 1988 150hp 2stroke evinrude --- Bogging

You are mixing the fuel 25:1 AND the VRO is working?

 

[emdsapmgr]

Re: 1988 150hp 2stroke evinrude --- Bogging

Is there some reason you don't take the engine back to the rebuilder? Unlikely it's a fuel delivery issue if the engine will run at WOT on occasion. It may be dropping spark to one or more cyls. Weak ignition components tend to fail once the engine heats up to normal operating temps. (may run fine when cold, but not when warmed up.) You'll want to run the engine through warm-up, then check the spark when you note that it's not making power. That engine will seem to run just fine on only 3 or 4 cyls when idling in neutral or when on the trailer. When you get the engine's exhaust 20" underwater and in gear, you need all 6 firing. An inductive timing light works fine as a spark checker, or you can do a cyl drop test with a set of insulated pliers. That engine has two power packs, one for each head. They can be swapped for spark testing purposes.

 

[keefallan]

Re: 1988 150hp 2stroke evinrude --- Bogging

Do a compression test also. This way you will be able to know how much pressure that you have in each cylinder. If you aren't making the right cylinder pressure, it won't run right anyways! Doing compression tests give me a peace of mind during the break in stage. It lets me know where the motor is(besides being on the back of the boat!!!LOL!!!). If your motor has no issues with sparking, it sounds like it may be running lean(at low speed). Try choking it when you are trying to get up on a plane. If it's running lean, it will pick right up when u choke it a little. But I would start at the beginning and do the basics: Check compression, check for any leaks, re-torque the heads(did you?), check coils, check your grounds, make sure that all linkages are smooth and loose moving. Do a spark check like EMD said.