Logo
FULL SITE MENU

Motor will not throttle up

B

Bo87

New member
Hello everyone, I recently purchased a pontoon boat with a 1991 mercury outboard motor/75hp. I've had it out on the water a few times and it ran great, no problems at all. I put it in the water a couple weeks ago now and it wouldn't throttle up? It cranks great, idles great, the motor pees like it sapost to, goes in gear great, it just will not idle up. With the fast idle or on its on while in drive. I took it to get looked at and the place called and said the motor is tired? The guy said somethan about is got to much pressure on the valves or pistons? Honestly I have no idea what he's talkin about and he said the motor needed rebuilding and it would be $1600-$1800. Any insight would be great, anything I might could try and do on my own, does he sound like he knows what he's talkin about? Thanks in advance.
 
Maybe I'm wrong but I don't believe Mercury was making 4 stroke outboards back then. If he thinks there's a valve issue definately get the engine away from him. To me it simply sounds like a linkage issue.
 
Are you certain it doesn't contain 10% (or higher) ethanol? Here in NJ, we can't buy any gasoline without the added ethanol. I'm only asking because that's what it's sounding like to me. Because, if it does have any Ethanol then you'd need to replace all of your gasoline hoses, etc, as it eats up Neoprene hoses that were made for Gasoline, but are NOT compatible with Ethanol at all.​
 
The fact that the fast idle does nothing leads me to believe linkage is disconnected or broken somewhere between the controls and the outboard. I know your engine is a 2 stroke I was just simply saying if the mechanic you took it to brought up valves right away... 2 strokes don't have them aside from reeds... If the engine ran fine and now suddenly only idles and responds to no throttle input whatsoever you need to start with the basics. Check all the mechanical connections between the controls and the engine. If a "mechanic" says an engine is tired and doesn't provide any reason why or any physical evidence to back it up then he is full of bs.
 
Thanks everybody for the info, I will check the gas station I got fuel from and find out about the ethanol. As far as checking the linkages and such I done that for about 2 hours prior to taking it to the mechanic, I mean I checked to see if all thangs were hooked up but did not check to see if one was broken. The more I thank about that the more I beleave it may be a broke cable inside the plastic sleeve because you can work the throttle perfectly fine on the side of the motor. And while I'm talking about that does anyone know how I would go about measuring a throttle cable or at least finding out how I can get one for my boat? It's a 89 Riveria pontoon boat, 24ft.
 
I agree with Jay, because you shouldn't be able to work your throttle at the motor end if the cable was connected. The best way to measure any cable is to remove it. That is, if you want one the exact length as the old cable. And you can probably order one from this site Marine Engine.. They are quick on getting things shipped out as well as great folks to do business with. You order the cable for the motor it connects to. Not for the boat it's used on.

PS: I didn't comprehend what you were saying when I went off on the Ethanol facts. Because, if the throttle was working, then it would have bogged down and quit running when you attempted to throttle it up had it been bad Ethanol. So as I said, I agree with Jay. Regardless, I sure wish they'd let us go back to having real Gasoline in NJ. As it is, "Ethanol is Death to ALL engines" as well as to Auto's in general.


​
 
We have quite a few stations around here with ethanol free fuel luckily. Although out of laziness the boat tanks usually get filled up on whatever pump the truck does...
 
Jay, I'm laughing on the laziness. I did find out that we can go to Lowes, and buy (Ethanol FREE) gasoline, but get this: It's by the small 32 FL OZ cans for $5.95 that comes already mixed 50:1 for two cycle or Straight Gasoline (Non Ethanol) for 4 cycle engines. Same price each. Is that a RIP OFF! or what! That is the largest amount they are aloud to sell, according to the sales person. But that's what I use in our lawn mower and weed eater. After having had to rebuild the carbs after they sat for a few weeks. PS: That gas is guaranteed to stay fresh for up to two years. Not bad.

PS: Come to think of it, I'm feeling a bit Lazy these days. After work on my son's motor out in the sun. lol
 
Last edited:
I can't remember the name of the company but there is a place outta Texas that sell that in I believe 5 gallon drums. I used to work on equipment used to extricate people in car crashes and s the fire departments used it in the gas powered pumps that ran the hydraulics. It was a little cheaper in bulk although I remember shipping was usually a hassle.
 
Back
Top