deductive troubleshooting help

spacerust

Petty Officer 2nd Class
Joined
Feb 18, 2008
Messages
190
i had my carbs cleaned out a few weeks ago and my boat ran fine. went out last week and everything ran really smooth. a few days ago i took the boat out fishing and decided to catch some bait in the shallows. it was a little windy so i used a push pole to try and stay from going aground. i had her idling for a while and then turned it off. when i tried to turn it back on the alarm went off and wouldn't turn off. the boat did start but i turned it off quickly wondering what was going on. i figured it probably picked up some mud or something and needed to be ran to clean it out. i turned it off and on about three times and the alarm stayed on. then all of a sudden it turned on and no alarm. still figuring it needed to wash itself out i ran her as normal. i did notice a slight loss of acceleration. well it wasn't a good trip because there was a lot of grass everywhere. i tried avoiding it and stopped to fish for about thirty minutes and when i was going to move i noticed she wouldn't get on plane at WOT. so i decided to head home. i thought it was the grass so i stopped a few times to clean it from the water intake? but it didn't seem like there were any there just on the nose. still wouldn't plane. i have a jack plater so i tried moving it up and down to see if i could get it to plane. nothing. checked compression all between 115-120. it is a 90hp evinrude on a 18' flats boat. 1973 motor. carbs cleaned. it did not overheat either. posted in props section thinking it could be spun hub. they suggested to post here. i have spark, check that as well. what else could cause this?
 

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,198
Re: deductive troubleshooting help

does that engine have different alarms for fuel restriction vs overheating
or is it just one generic tone.?
 

spacerust

Petty Officer 2nd Class
Joined
Feb 18, 2008
Messages
190
Re: deductive troubleshooting help

honestly i don't know. it sounded like it was coming from the control box, not the engine. i was thinking last night i know it didn't overheat but am wondering if the impellar would have something to do with this. should i check to see if it had anything in it? but like i mentioned before it didn't overheat and tell tale seemed fine.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: deductive troubleshooting help

1973 only has an overheat alarm.
 

spacerust

Petty Officer 2nd Class
Joined
Feb 18, 2008
Messages
190
Re: deductive troubleshooting help

could it be something in the impellar? should i check that out?
 

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,198
Re: deductive troubleshooting help

if the alarm says it overheated it overheated til proven otherwise,
that seems prudent to me.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: deductive troubleshooting help

The impeller is the first suspect. Also, you may have sucked up some debris (grass/sand) through the water intakes. I'd pull the thermostat housing apart and have a look. If you find anything there, I'd probably pull the head covers off and check them for debris also. Not sure what you mean by the telltale was fine, since this engine did not come with one from the factory.
 
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