90hp Force will not idle in the water - Moderated Discussion Areas

  ContinuousWave
  Whaler
  Moderated Discussion Areas
  ContinuousWave: The Whaler GAM or General Area
  90hp Force will not idle in the water

search | FAQ | profile | register | author help

Author Topic:   90hp Force will not idle in the water

mbaka406 posted 10-03-2013 01:11 PM ET (US)
I have a 1990 90hp Force that I picked up this summer. It idles fine on the hose/muffs, but when I put it into the water it will not idle. I replaced the water pump thinking that might have something to do with it. It runs great at the top end. Any ideas?

Einar posted 10-03-2013 04:00 PM ET (US)
Boy does this sound familiar. I had the same symptoms with a 1981 Johnson 75HP.
It was the fuel pump, and small leak between the pump and 1 of the carburetors.
Good luck chasing this down.
Al

6992WHALER posted 10-03-2013 04:32 PM ET (US)
Might be a blown engine.
My 1991 90hp Force did the same thing last year. Turns out it blew the #3 cylinder. Check out the engine before you put anymore money into parts.
jimh posted 10-04-2013 10:03 AM ET (US)
Seeking advice for repairs is best done in the REPAIRS/MODS discussion. This discussion, THE GAM, is used for general topics that do not fit into the other, more specific, forum topics.
jimh posted 10-04-2013 10:05 AM ET (US)
Outboard engines idle much different in the water than they do when running on a hose adaptor. In the water the exhaust path is blocked off by the water, and there is much more back pressure on the engine. This is normally relieved by some sort of idle exhaust by-pass route.
It is best to adjust the engine idle speed when the boat is in the water and the engine exhaust is submerged.
tedious posted 10-04-2013 11:54 AM ET (US)
OK, it can't be the fuel pump because it runs fine at speed. Ditto electrical / spark problem. Best bet is that the idle passages in one of your carbs are clogged. You can test that on the muffs, at idle - block off the air going into the carbs one at a time. When the clogged carb is blocked, the idle speed will not change - when the others are blocked, it won't. Clean and rebuild the clogged carb.
Tim
tedious posted 10-04-2013 12:05 PM ET (US)
Ahem - when the carbs which are working fine are blocked, the idle speed WILL change. Jim, please edit if you can. Thanks.

Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.

Author	Topic: 90hp Force will not idle in the water
mbaka406	posted 10-03-2013 01:11 PM ET (US) I have a 1990 90hp Force that I picked up this summer. It idles fine on the hose/muffs, but when I put it into the water it will not idle. I replaced the water pump thinking that might have something to do with it. It runs great at the top end. Any ideas?
Einar	posted 10-03-2013 04:00 PM ET (US) Boy does this sound familiar. I had the same symptoms with a 1981 Johnson 75HP. It was the fuel pump, and small leak between the pump and 1 of the carburetors. Good luck chasing this down. Al
6992WHALER	posted 10-03-2013 04:32 PM ET (US) Might be a blown engine. My 1991 90hp Force did the same thing last year. Turns out it blew the #3 cylinder. Check out the engine before you put anymore money into parts.
jimh	posted 10-04-2013 10:03 AM ET (US) Seeking advice for repairs is best done in the REPAIRS/MODS discussion. This discussion, THE GAM, is used for general topics that do not fit into the other, more specific, forum topics.
jimh	posted 10-04-2013 10:05 AM ET (US) Outboard engines idle much different in the water than they do when running on a hose adaptor. In the water the exhaust path is blocked off by the water, and there is much more back pressure on the engine. This is normally relieved by some sort of idle exhaust by-pass route. It is best to adjust the engine idle speed when the boat is in the water and the engine exhaust is submerged.
tedious	posted 10-04-2013 11:54 AM ET (US) OK, it can't be the fuel pump because it runs fine at speed. Ditto electrical / spark problem. Best bet is that the idle passages in one of your carbs are clogged. You can test that on the muffs, at idle - block off the air going into the carbs one at a time. When the clogged carb is blocked, the idle speed will not change - when the others are blocked, it won't. Clean and rebuild the clogged carb. Tim
tedious	posted 10-04-2013 12:05 PM ET (US) Ahem - when the carbs which are working fine are blocked, the idle speed WILL change. Jim, please edit if you can. Thanks.