Very little water flow at low speed (86 Evinrude 9.9)

[Fronterra]

My 86 Evinrude 9.9 has very little water flow at low speeds (just above idle). I noticed this yesterday when I was trolling on the lake. At just above the idle I lose the solid stream flow of water out of pee hole and get a mix of water spray and exhaust. At normal to high speeds I get a good, solid stream of water. I am assuming the cooling water impeller runs on engine speed so faster the engine, faster the impeller turns but should I get nearly no flow at above idle speeds? Thanks

 

[ondarvr]

Re: Very little water flow at low speed (86 Evinrude 9.9)

A loss of flow, plus steam and exhaust out the pee tube typically means the head gasket is blown.

 

[Fronterra]

Re: Very little water flow at low speed (86 Evinrude 9.9)

Wouldn't that be true at all speeds or just low speed?

 

[kbait]

Re: Very little water flow at low speed (86 Evinrude 9.9)

Replace impeller and inspect lower water tube grommet. A weak impeller or improperly sealing grommet where water tube seals to pump housing will cause your problems. Test in a barrel/lake afterwards and if it's not resolved, post back.

Good luck!

 

[Fronterra]

Re: Very little water flow at low speed (86 Evinrude 9.9)

I just ran the engine on my muffs and I have a good, steady flow of water at very low speed. Could it be the position of my tilt?

 

[ondarvr]

Re: Very little water flow at low speed (86 Evinrude 9.9)

Wouldn't that be true at all speeds or just low speed?

It depends on the size of the hole in the head gasket, a very small hole (gap) may not push water out of the way at all speeds and may do it intermittently. I had one that did this.

The rubber grommet is also a potential problem on these motors, it swells and restricts the flow, which leads to overheating and a blown head gasket

 

[ondarvr]

Re: Very little water flow at low speed (86 Evinrude 9.9)

I just ran the engine on my muffs and I have a good, steady flow of water at very low speed. Could it be the position of my tilt?

On muffs you are sort of force feeding the system. At any time if air or exhaust blows out the pee tube you have problems.

 

[Fronterra]

Re: Very little water flow at low speed (86 Evinrude 9.9)

How difficult is it to check the grommet and head gasket?

 

[ondarvr]

Re: Very little water flow at low speed (86 Evinrude 9.9)

You need to pull the power head off, it's sort of a hassle, but not hard to do (that is if the bolts aren't corroded). Taking the head off is very easy.

 

[Fronterra]

Re: Very little water flow at low speed (86 Evinrude 9.9)

Even with a potential head gasket leak or grommet restriction wouldn't the engine overheat? I have had no overheating or performance issues with the engine. I just happened to notice the low flow yesterday.

 

[kbait]

Re: Very little water flow at low speed (86 Evinrude 9.9)

First things first. Run motor in barrel or lake to test waterpump. You can't really tell anything using muffs and forcing the water through.. although you could tell if it's totally clogged.

If it's spitty/steamy at low speeds, again, your impeller is weak or you have a leak/obstruction somewhere. Pull lower unit, change out impeller, check grommet and test.

I'm skeptical about exhaust/water from the indicator. Probably steam from the bit of water that's there when flow is interrupted. Skip the head gasket for now, and replace your impeller. If it's been a few years, or you don't know when it's been changed, you need to do that anyway. Check the side of the lower grommet for a rip.. quite common.

Here's some expert advice: http://www.leeroysramblings.com/Lower_unit.htm

Good luck!

 

[ondarvr]

Re: Very little water flow at low speed (86 Evinrude 9.9)

How would you know if it's getting too hot? Mine ran great for a couple of months doing the exact same thing, I just knew there was something wrong and took it apart. The leaking head gasket didn't even show up doing a compression test.

 

[Fronterra]

Re: Very little water flow at low speed (86 Evinrude 9.9)

First things first. Run motor in barrel or lake to test waterpump. You can't really tell anything using muffs and forcing the water through.. although you could tell if it's totally clogged.

If it's spitty/steamy at low speeds, again, your impeller is weak or you have a leak/obstruction somewhere. Pull lower unit, change out impeller, check grommet and test.

I'm skeptical about exhaust/water from the indicator. Probably steam from the bit of water that's there when flow is interrupted. Skip the head gasket for now, and replace your impeller. If it's been a few years, or you don't know when it's been changed, you need to do that anyway. Check the side of the lower grommet for a rip.. quite common.

Here's some expert advice: Lower Unit

Good luck!

I read the article. It seemed cut and dry but have you ever removed a lower unit? How difficult is it to remove and then remove impeller?

 

[Fronterra]

Re: Very little water flow at low speed (86 Evinrude 9.9)

First things first. Run motor in barrel or lake to test waterpump. You can't really tell anything using muffs and forcing the water through.. although you could tell if it's totally clogged.

If it's spitty/steamy at low speeds, again, your impeller is weak or you have a leak/obstruction somewhere. Pull lower unit, change out impeller, check grommet and test.

I'm skeptical about exhaust/water from the indicator. Probably steam from the bit of water that's there when flow is interrupted. Skip the head gasket for now, and replace your impeller. If it's been a few years, or you don't know when it's been changed, you need to do that anyway. Check the side of the lower grommet for a rip.. quite common.

Here's some expert advice: Lower Unit

Good luck!

I was on the lake yesterday running the engine jus above idle (trolling) and I noticed the low flow. As soon as I bump up the throttle a tiny bit I got the flow. I am agreeing with you that the impeller maybe worn. I just hate tearing into something I have never done before. Mechanically I am ok to do it, just hate to run into an issue and it seems that Murphy always shows up at the wrong time.

 

[kbait]

Re: Very little water flow at low speed (86 Evinrude 9.9)

Removing lower unit:

When you get these 6 bolts removed, the gear case unit should drop down about 1/2”. If it does not you may have to tap it with a plastic mallet. Shift the gearshift into forward. When the lower unit does slide down, there will be, inside the housing in the front right hand side, a connector that is a strap with 2, ?” tapped holes top and bottom. In these holes are 2 bolts that are screwed in sideways connecting the upper and lower shifting rods. These bolts go in a circular groove of the shifting rods, and hold it in place. Remove only the top screw. It has a 3/8" hex head and also a screwdriver slot. Once this bolt is removed the gear case unit can be moved downward and off.

Changing impeller:

Remove the 4 waterpump housing mounting bolts, slide housing up and off drive shaft. Replace impeller, making sure the veins are installed correctly by spinning driveshaft clockwise while sliding impeller into housing. Replace mounting bolts, check grommet, install lower unit, making sure to line up the water tube into grommet and re-connect shift rod. Secure lower unit mounting bolts and test.

Good luck!

 

[Fronterra]

Re: Very little water flow at low speed (86 Evinrude 9.9)

Removing lower unit:

When you get these 6 bolts removed, the gear case unit should drop down about 1/2”. If it does not you may have to tap it with a plastic mallet. Shift the gearshift into forward. When the lower unit does slide down, there will be, inside the housing in the front right hand side, a connector that is a strap with 2, ?” tapped holes top and bottom. In these holes are 2 bolts that are screwed in sideways connecting the upper and lower shifting rods. These bolts go in a circular groove of the shifting rods, and hold it in place. Remove only the top screw. It has a 3/8" hex head and also a screwdriver slot. Once this bolt is removed the gear case unit can be moved downward and off.

Changing impeller:

Remove the 4 waterpump housing mounting bolts, slide housing up and off drive shaft. Replace impeller, making sure the veins are installed correctly by spinning driveshaft clockwise while sliding impeller into housing. Replace mounting bolts, check grommet, install lower unit, making sure to line up the water tube into grommet and re-connect shift rod. Secure lower unit mounting bolts and test.

Good luck!

Cut and dry. Appreciate the help. I will not be able to get it done until after thanksgiving but I will post the results

 

[Fronterra]

Re: Very little water flow at low speed (86 Evinrude 9.9)

How would you know if it's getting too hot? Mine ran great for a couple of months doing the exact same thing, I just knew there was something wrong and took it apart. The leaking head gasket didn't even show up doing a compression test.

I guess I wouldn't know until the engine seized up.

 

[raczekp1]

Re: Very little water flow at low speed (86 Evinrude 9.9)

under powerhead is water tube gromet.slowly this gromet can lock up, restricting water flow. i had the same problem
my advice is to put new impeler, check termostat also.
if week stream will occure, i woud ter down powerhead and instal new water tube grommet and water jacket gaskets

 

[CatTwentyTwo]

Re: Very little water flow at low speed (86 Evinrude 9.9)

I had the same problem with my 84 9.9, very little flow, over heat and steam at trolling speed but okay at higher speed. Checked my records and it had been 10 years since I had last replaced the pump.:facepalm:
A new water pump kit fixed it up and I change it out every 5 years now.

 

[Fronterra]

Re: Very little water flow at low speed (86 Evinrude 9.9)

I had the same problem with my 84 9.9, very little flow, over heat and steam at trolling speed but okay at higher speed. Checked my records and it had been 10 years since I had last replaced the pump.:facepalm:
A new water pump kit fixed it up and I change it out every 5 years now.

Thanks for the info. Same exact symptoms as me (not over heating though). I probably never would of noticed had I not decided to troll yesterday. Normally I just get to my fishing spot then use my minn kota. Plan on taking the father in law fishing friday so I will take it easy until I get my new pump.