1989 48hp spl rpms seem limited

I have a 1989 evinrude 48 hp spl which last year when i took out the overheat alarm activated. Since then, i have not been able to get it to full throddle except by directly injecting fuel via the cold start injector/ choke. i have tried idling for several minutes to reset, replaced fuel line/bulb, and thoroughly cleaned the carb & jets. Fuel filter seems fine.Seems like something is limiting the rpms to about 30%. Water pump semms to be working fine(Good water pressure).Motor idles and sounds solid.<br /> ANY IDEAS

Re: 1989 48hp spl rpms seem limited

you might wanna check the compression and spark. Lots of times motors can idle and sound surprisingly good when they've lost 1 cylinder (even when it's a twin). They only fall on their face when you put some load on them.<br /><br />Brent

Re: 1989 48hp spl rpms seem limited

Agree with BF. At best, I think you may have popped a head gasket.<br /><br />Is either one of the spark plugs real clean looking? If so, you have water injestion in a cylinder.

Re: 1989 48hp spl rpms seem limited

If it was a cylinder problem, why would the the engine rpms & boat speed increase to normal by injecting fuel directly into carb via cold start choke. I first thought it was a fuel delivery problem, however after reviewing the manual, I noticed that the engine has a rpm limiter which activates wnen the overheat alarm goes off. It says to reset this the engine should idle in gear for several minutes. I' ve tried this to no avail.Is there any way to reset this limiter manually?

Re: 1989 48hp spl rpms seem limited

Striperbob,<br /><br />I have the exact same motor, same year. Ran fine all the years that I owned it (bought it used 5 years ago). Then one day ran perfect for 15 or so minutes then then out of the blue it shimmied and shook, seem like it wanted to jump off the transom. I slowed down and it ran fine under 2k rpm above that and it ran bad. But when I choked mine it didn't run any better above the 2k rpm. I checked all the things they say to check, compression, temp., spark, fuel all was ok. Reluctanly I replaced the PowerPak and I runs fine now. I bought a Oem part from dealer, $109.00.<br /><br />Not really sure if its the same problem your haveing as your weren't real discripted about your symptoms. But you did mention the rpm limiter which is known as S.L.O.W. (speed limiter overheat warning) if I remember right.<br /><br />Hope this helps.<br /><br />Beck