2005 90 ELPTO Lost Top End Power and RPM's

[mike37909]

My 90 elpto on my pontoon wont rev past 3800 RPM's anymore. This happened last time I was out on the boat. It was running normal and would get to 5500 or so but then after using the trolling motor for a few hours I had no speed or rpms past 3800 on the way home. I had put 5 gallons of new gas in the 20 gallon tank since it was almost empty. The gas has no ethanol according to the gas station.
Sunday I put another 5 gallons in and a can of sea foam. The motor started normally and ran normally ( after warming up for a while). It runs smooth just no power. It seems like my boat has gained weight but she is floating on her lines.
The motor will rev high in neutral or if you trim it up too much. My water pump is peeing good over 15 PSI on the gauge also. I use 93 octane gas and mercury synthetic 2 stroke oil. Motor is a 2005 model. I had the boat for a year now and have done no maintenance. It didnt come with a manual. I plan on getting the service manual.
Thoughts?

 

[Texasmark]

Re: 2005 90 ELPTO Lost Top End Power and RPM's

First guess is a clogged fuel filter, or a bad fuel pump. I have had ignition problems with my pulse packs, but they surfaced at low speeds. Other problem was a stuck stat, but that was only at low speeds as the engine has a pop-off valve for high speed operation that bypasses the stat.

Since fuel flow it the most at high speeds, a constricted filter would show up earliest at the highest speeds. But it is interesting that it did it immediately, not progressively as one would expect in a filter clogging up.

Pee on that engine comes off the exhaust manifold directly and cannot tell you what your block cooling circuit is doing. Only your OT alarm can do that and it kicks in at 190F......constant warning horn.

On deciding on possibly the filter or fuel pump, squeezing the bulb at high speed would do 3 things:

1. If it is collapsed, you have a clog in the tank in the screen protecting the fuel pickup tube or a malfunctioning bulb and it is clogging the fuel line...not very common.

2. If it is semi full of fuel squeezing it removes the task from the fuel pump and if the engine resumes normal WOT rpm's the fuel pump must have developed a hole in the diaphragm. This squeezing may even force fuel through a clogged filter if that is the case.

3. Last would be a power pak failed due to heat. Hard to listen to that triple and hear one failed. Performance is the only way you (I) can tell, unless you are in the shop, have the engine in a test tank with a test wheel, run at WOT and check the spark then......hard to do it on the water.

My 2c,

Mark

 

[mike37909]

Re: 2005 90 ELPTO Lost Top End Power and RPM's

I squeezed the bulb but not at WOT cause I was by myself. I had a vision of the boat accelerating and me falling in the 41 degree water, watching the boat drive away. The bulb was hard and full though. Where is the fuel filter on this motor? Is it hard to get to? I bet it is bad gas, since it started the day I put some gas in it. The gas was new but who knows if it was good. Maybe the sea foam will work it out.

 

[mike37909]

Re: 2005 90 ELPTO Lost Top End Power and RPM's

Turns out I had a non running cylinder. I was spraying carb cleaner in the carbs and I noticed one cylindar did not make it run rougher when I sprayed in it. I pulled the plug wire and it ran the same. I swapped power packs with the middle cylinder and the middle went dead so I got a new power pack. 79.99 but better than pulling the boat to the shop. Revs are back to normal now. I am surprised how smooth the motor runs with a dead cylinder.