View Full Version : Problems with force 90 hp outboard

Lee Herring
04-11-2004, 03:54 PM
" My motor loses rpm's after about 15 minutes of riding. Sometimes it will straigthen up after it sets and sometimes it won't. It only turns about 1500 rpm's at full throttle. Ignition boxes are new, ignition coils are new, spark plugs are new, Have drained the gas tank and it's clean, have cleaned all three carbs. number three had some water in it but now it is clean, I unhooked the temp sensor to see if it was cutting out due to heat and it didn't change, I'm running out of ideas. There is a small hose coming off of the intake under the bottom carb. It is not hooked up to anything and it can suck air in through it even water if it gets to it. Where should this hose be going to? Also are there any ideas on the rest of the problems I am having with this motor? The engine runs smooth even though it will not rev up after this takes effect. It idles good and has a very strong spark. Could my lower unit be seizing up causing it to lose rpm's? "

04-11-2004, 10:11 PM

Lee Herring
04-12-2004, 06:12 AM
I checked the vent hose and it is not stopped up. I have also run a compression test and it seemed o.k. no1 cyl.115-- no2 cyl. 115-- and no3 cyl.120. Thanks for your reply

05-21-2004, 02:56 PM
" i took ny boat out for the first time this year it had new gas and new oil i ran it for 20 minits with the water hose befor i left home. everything ran great, i put it in the water it started find fine, when i put in gear it keep on cutting off. i then let it idle and it cause a rod bearing to go. i didnt do nothing wrong, has someone else had this problem? is it a manufactor problem they are having with this 90hp mecury froce. any advice will help. they want 3200.00 to fix it. 98 "

05-12-2006, 08:44 PM
"Double check the fuel supply line for any kind of restriction - I had a kinked fuel line on my 90 hp Force with the same results - it would idle along but wouldn't go any faster than an idle.

That hose you are talking about should hook up to a ninety degree fitting on the bottom of the air intake shroud that feeds air to your carbeurators. It's very hard to see when assembled because it is on the bottom (leg side).