1986 225hp Evinrude E225TXCDA runs rough at idle, bogs and shutsdown when throttled up

I have posted some questions before when I was diagnosing the ignition system. Afer performing the diagnostics, I replaced the timer base, re-glued the flywheel magnets, replaced two bad coils, and finally got fire on all cylinders using a 8 gang spark tester with 7/16" gap. I have not serviced the carbs, but did clean out the bowls and flush new fuel through them until I got no debris. I have cleaned the high speed jets and the air bleed orifices on each carb, interesting, found a lathe turning behind one of the orifices! Don't know how long the previous owner dealt with that! The compression on all cylinders is in the 90psi range. The engine always starts easily but seems to "load up" with fuel and bog down until it is on about two or three cylinders. It will shut down if you try to throttle up. Curiously, once it rev'ed up and planed out at high rpm for just a minute, but then started to hesitate and eventually bogged down to a few cylinders. My question is: Does this just sound like a carb problem where I just need to refurbish them? What function of the carb would cause the engine to run too rich and bog down... needle and seat, more trash in carb, etc? Also, pushing in the primer or pumping the bulb does not alleviate the issue, so fuel is getting into the carbs, just too much at the wrong time. I have set the sync and link per the manual, but not been able to set the high speed timing yet due to the running problem. I'm ready to start carb overhaul, but just want to be sure I'm on the right track.

Did you buy the engine with all these power level problems ? Or was it always running perfect & has suddenly gone bad on you ?

If we accept that you have good spark & slow speed ignition timing. Then we come up with fuel problem. Contaminated fuel with just about anything possible.

I can believe that a 1986 225 hp has been pushed a lot at WOT & may have some serious gasket seal leaks all over.

Somuch to check on a older engine.

While it's difficult to give the full history of this motor when starting a thread, I'll try to give the background. This engine was acquired after an out-of-state purchase by a friend where it came along as the old engine that had been replaced. He didn't want it so I told him that I would take it and see if it was worth restoring. When I saw that it was in remarkable shape for its age and the initial compression checked out (all cylinders over 90 psi), I decide to put some money into it and try to bring it back to life as my "new" re-power" for my 1979 23' Robalo cuddy. I had a 1979 150hp Evinrude that had broken a ring and had been sitting for almost a decade. Upgrading to a 225hp was quite a jump, but the boat is rated for 250hp and the transom had been replaced previously, so I felt comfortable with the increase in power. This engine was missing some outer parts (shock absorber covers, thermostat covers and thermostats, cooling hoses, etc.) but the real challenge was that the wiring had been chewed on by a rodent. I had to replace the wiring harness, the fuel hoses up to the fuel pump, the solenoid primer valve, all spark plug wires, but everything else is working, i.e., PTT, water pump, with the exception of the timer base and two ignition coils. When I got all cylinders firing, it still wants to bog when the throttle is advanced though that one time it ran for a minute at WOT. I'm just trying to make sure there is nothing else to check before spending over $150 for the carb rebulid kits.

Do the rebuild of the fuelpump. Clean out the fuel tank / tanks.

Can you post the wiring diagram / electrical schematic of the engine ? I worked on a old Merc with a mercury tilt switch that had been DIYed to a incorrect position That prevented starting the engine unless the motor was trimmed all the way in.

So much odd ball stuff is added each year to some engines.

That 1 minute of good WOT is a good indication of a filthy fuel tank & the crap chunks blocking the pickup tube. Can also be water slugs going thru the fuel system.

I get very frustrated when I try to help people bring back the " dead ". In reality, everything needs to be tested & cleaned to see if it is still good

I agree that the WOT is a good indicator, if anything, that the ignition system is working. The easy starting indicates good ignition, too. When I drained the carb bowls afterwards, there was some varnish residue and hose residue that would have caused the engine to hesitate due to fuel restriction. I figured that the sudden fuel flow moved any restrictions to the carbs when it ran a WOT. FYI, I was running on a new Moeller 9 gal. tank with fresh non-ethanol fuel and OMC oil, so contaminated fuel would not be the problem. I also previously took apart the fuel pump and cleaned and inspected the diaphram which seemed in good shape. I'm just trying to eliminate any issues other than the carbs being refurbished. I'll change more of the small hoses while I'm doing it, too. I'm just trying to cover all issues that would cause this problem before I start the carb overhaul. Would hate to miss a simple fix that I overlooked!

My smaller fuel pump had no visable damage to the tiny rubber check valves or the diaphram. But. The diaphram was stretched a fair amount. so the rebuild kit went in.

I vote for somebody did a DIY job on the carbs. & set the floats too high. Or a float is sticking open on a carb. That 1 good run of 1 minute.

You can no longer avoid the carbs.........

I always use all the new parts in a kit.......Never know when that old part will let go.

Good luck on a white cloth with them.

Thanks. I think that I'm going in the right direction. I'll post the results when I'm finished and give it a test.

After carb rebuilds, seemed to solve the problem with bogging. Engine now runs about 5300rpm at WOT, pushing my 1979 23' Robalo just over 30kts. Starts fine and doesn't stall when manuevering at idle speeds. Even the smoking has reduced to a small amount. I would like to see it run smoother at idle speed (it seems to shake or chug, but doesn't stall). I'm going to check the link/sync one more time as well as the fast speed timing just to be sure all is right.

It's been awhile since I have posted on my engine, but wanted to add some of my latest observations during my spring outings. I've check the link/sync over and over to get it right and the engine cranks well and runs strong at WOT. With a new tachometer, I've been able to observe it at different rpms and have a question about performance under 2000rpms. When you back off on the throttle down to 2000rpms, the engine goes from running smoothly, to a "chugging" condition. I have heard that these engines had some orifice and jets issues with the original carburetors and when I checked, it has the original carburetors on it. Does anyone remember what the problem was and what the remedy Evinrude suggested?

chessbass said:

It's been awhile since I have posted on my engine, but wanted to add some of my latest observations during my spring outings. I've check the link/sync over and over to get it right and the engine cranks well and runs strong at WOT. With a new tachometer, I've been able to observe it at different rpms and have a question about performance under 2000rpms. When you back off on the throttle down to 2000rpms, the engine goes from running smoothly, to a "chugging" condition. I have heard that these engines had some orifice and jets issues with the original carburetors and when I checked, it has the original carburetors on it. Does anyone remember what the problem was and what the remedy Evinrude suggested?

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UPDATE: After setting idle down to 750rpms in water, it helped with the rough running and smoothed out. Now I'm noticing that the engine does not want to go over 5000rpm when I try to go to WOT. It runs fine at other rpms so I'm looking for a way to see if its not getting fuel or the timing is off. I've checked the butterflys and they are perfectly aligned at full throttle. Any suggestions on how to proceed with a diagnosis?

Wow! Didn't realize that I had not followed up on my last post. For any followers, I solved the WOT issue by directly connecting the fuel hose without a quick connector. It must have been pulling air at higher rpm and leaning out. Hope this helps anyone who was following this thread.