'88 Force 85hp exhaust boot split open. I need help identifying a plastic part.

[DunbarLtd]

My exhaust port boot or whatever its called split open last time on lake.

I have provided a link to some pics. I found a piece of plastic that is supposed to go inside the rubber boot but i cant tell which way its supposed to sit as the diagrams are too blurry. I know it goes on the tapered end but the two sides of the plastic insert are not the same. Tall or short side towards engine cover perhaps. Or does it even matter?

Which way does it face while inside the boot?

Here is the link:

https://imgur.com/a/Bfc8L

Thanks and have great weekend!

 

[Nordin]

Do not know which side you mean is short or tall side.
The side with larger diameter shall be towards the cover. The plastic part is called an insert and should be inside the rubber boot and will support the spring.
The spring will go over the smaller diameter but not the lager.

 

[redfury]

I'm not even running with one of those, I never saw it when I replaced my boot. I would guess that it goes on top of the spring inside the boot to protect the end of the boot from the spring, as the spring tension will be against the motor leg on the other side.

 

[DunbarLtd]

Do not know which side you mean is short or tall side.
The side with larger diameter shall be towards the cover. The plastic part is called an insert and should be inside the rubber boot and will support the spring.
The spring will go over the smaller diameter but not the larger....

Ok got it thanks a bunch!

 

[jerryjerry05]

Make sure you use a stainless clamp.

Something to think about??
I wonder why it blew?
​Usually only a backfire would cause the split???

​After the repair, use a can of starting fluid around the intake sides of the motor.
See if it makes any difference in the way it runs.
​If the spray makes it stumble,run smooth or coughs?? Then it's got a bad gasket and sucking air.
The bad gasket can make it backfire??

 

[DunbarLtd]

Make sure you use a stainless clamp.

Something to think about??
I wonder why it blew?
​Usually only a backfire would cause the split???

​After the repair, use a can of starting fluid around the intake sides of the motor.
See if it makes any difference in the way it runs.
​If the spray makes it stumble,run smooth or coughs?? Then it's got a bad gasket and sucking air.
The bad gasket can make it backfire??

Couldnt get a clamp to stay on it seemed to wide and would slip off. I used a ziptie and that worked. No more exhaust smoke leaks.

Bad gaskets you say.....?

Yea its possible. It coughs and sneezes quite a bit when i first try to start it. Then randomly itll do it throughout the day. At times itll fire right up with no sneeze at all.

When i started it recently when boot blew i had stored it as we moved. Maybe a month. First crank i primed the bulb and put throttle in fast idle and BANG! Sounded like a gunshot. Used the choke as usual. Not sure if fast idle start would cause backfire or cuz i hadnt started it in a while. Anyways...

Then the motor wouldnt start and if it did it wouldnt run long. I took off cover and it started right up. But didnt backfire that time. Put cover on and it stalled. Thats when i knew something wasnt right and upon further inspection saw the boot split wide open.

I installed a new one and took it out couple days ago. It didnt backfire this time but it took several cranks to get it started. Then it idled at boat dock and made it all way past no wake zone. Ran ok for few minutes to our spot.

I noticed carbs were leaking while out there. Out of the high speed jet or weep hole??? In middle carb.

The bowls were leaking too and the air plenum gaskets were soaked through and seeping a tad. Mounting gaskets are nice and sealed.

Took off the top carb when i got home and noticed two things. First is that the bowl wasnt parallel to the carb surface like its supposed to. The float is good and floats though.

Two....The needle was ok but i noticed it has a rubber tip. It didnt look deformed. But the part im not too informed about is the replacement needle with the correct corresponding part number does not have a rubber tip. I have a solid brass seat. Im not sure if i need a needle with a rubber tip or the metal tip will work with the brass seat???

And when you say gasket??? Which one would you be referring to? Any of the carb gaskets or like a head gasket, etc????


Thanks for the reply. I ordered a new gasket set and carb kit to see if any of it will help with the backfiribg/sneezing. Of course ill set the floats correctly as well.

The air screws are set to about 1 1/8 turns out and she smokes quite a bit idling but im ok with that. It stays idling for the most part. Just sneezes more than i think it should.

Any other input would be appreciated. Take care.

 

[jerryjerry05]

The solid needle won't work right in the brass seat.
​The needle needs to have the rubber tip.
​You seat might not be able to be replaced?? be careful as lots have ruined the carb trying to get the seat out.

If the rubber tip isn't deformed?? re-use it.

​Gaskets: any gasket on the intake side, carb, the gasket under fuel pump, the 3 covers on the intake side.

The slow speed cough could be the carbs need setting up right.
​Top posts: there is one called a Link and sinc.
​Do that and see if it helps.

And some motors cough no matter what you do.

​Smoke at slow speeds.
After you run at higher speeds the smoke should clear up.

 

[DunbarLtd]

Ok thanks. I didnt think the solid tip needle would work. I wont try to remove the brass seat. It looks fine.

I do notice the smoke clears up at speed though.

Also, I cant seem to find a part number for the rubber tipped needle. I believe Sierra makes them but all i can find are the solid tipped ones at the moment and they are oem i believe the part number is

F10234 made by Mercury Quicksilver OEM.

Unless these new ones have a rubber tip?
Its tough to tell in the pictures online but im pretty sure they are the ss solid tipped ones.

Ill just reuse the old ones as im sure they are fine. Prob just needs to be cleaned and synced and gaskets and i think itll be good to go.

And when you say "intake covers" im not sure what you are referring to? Please excuse my ignorance. Take care.

 

[jerryjerry05]

The stbd. side where the fuel pump mounts.
That's an intake port cover.
There are 3 on an 85hp.
The fuel pump is mounted on the middle one.

​ONE 1 one backfire can blow the gaskets on a port cover.
​That's when the spraying starter fluid around the port covers helps ID a leak.
It sucks in and blows out and can cause a cough, miss and a backfire if a gasket's bad.

 

[DunbarLtd]

The stbd. side where the fuel pump mounts.
That's an intake port cover.
There are 3 on an 85hp.

Ok i removed the fuel pump and that gasket was fine.

I dont see the other two ports and no diagram shows it. Ill look through my seloc manual but im sure they are are right on each side of the fuel pump? Will i have to remove all 3 coil packs? Theres a brackets they mount to that takes up alot of space and i cant see whats behind it.

The diaphragm looks good too but im not sure how to test it???

Thanks again...have a good weekend.

 

[jerryjerry05]

The fuel pump mounts ON the middle port.
You should be able to see all 3 without removing anything.
But, you'll need to remove the power packs and coils to remove them.

Put the pump back on and do the starter fluid test.

 

[DunbarLtd]

Ok i see them now. The gasket i was referring to was the fuel pump gasket now that i have looked at the diagrams. I see the transfer ports and gaskets as well. I will do the test and see how it goes.

How often would one need to clear the recirculation system (cylinder drain). I am aware there are screens/reeds in there that get gunked up. And when its clogged the motor smokes too much??

But the Seloc says this isnt serviceable???

Any input on this?

Thanks again. Have a good day sir.

 

[jerryjerry05]

Seloc is a really poor service manual.
​And yes the cyl. drain is serviceable.
​The screen gets filled with bits of carbon and clogs.
​The screens F93811 are really hard to get.
​You might be able to find them on e-bay? Maybe Franz Marine?
​You can try: soaking them in carbon remover, Power Tune or Engine Tuner.
​Seafoam does nothing for removing carbon.
Let them soak and try a very soft brush??

 

[DunbarLtd]

Yes ive noticed many parts for these Forces are obsolete so that doesnt surprise me. Ill have to take that cover off and check. Im guessing its never been cleaned out so after 29 years im sure its nasty in there.

And ive found a few parts on ebay. Sometimes its the only option.

Ive never seen those carbon cleaners. Do they sell those at local auto stores?

I hear people use Yamalube Ring Free in these 2 strokes as well. Guy at parts desk here local boat dealer also said to use it.

What do you think about usung that stuff? How do you keep yours clean???

 

[DunbarLtd]

Ok so i removed all the bolts from the cylinder drain cover in order to clean that screen and its stuck on good. Its soft aluminum of course so any advice on how to pry off that cover without marring it to hell would be helpful.

 

[DunbarLtd]

Alright i made some progress. I was able to remove the cover and inspect the screen and reeds. The screens were not completely caked and closed up but there was some crud built up around the edges. Im sure something was able to get by but it definitely needed cleaning.

So I completely cleaned them and made sure the little jets were clear as well. Reeds looked fine.

I did notice on the very bottom edge of the drain gasket it looked wet through. Maybe it was leaking there???? Although the gasket wasnt torn. So im not sure.

I ordered new gaskets as the old ones were crunchy and stuck to the surface as i removed the cover.

And while i was in there i decided to rebuild the fuel pump. The diaphragm was a little stiff. All new gaskets as well.

In a few days when the parts arrive ill reassemble and do the starting fluid test.

Thanks for all the help jerry. Enjoy your week.

 

[DunbarLtd]

Also i forgot to ask....do you spray any type of gasket sealer on the cylinder drain gaskets or just fit them on dry?

 

[jerryjerry05]

I use a sealer of some kind.
I use OMC's gasket sealer.
A thin coat of RTV would work.

 

[DunbarLtd]

Ok ill use some high tack i have on hand. Thanks.

 

[redfury]

I had the bang just like yours and tore/blew the boot wide open and when I replaced it, the engine was running like crud, smoking...my fuel pump diaphram was torn. So, I fixed that, but now when I'm on the water, it runs great away from the dock, but starts to chug like the fuel line is choking out, but the primer bulb is still firm and pumping it didn't solve any problems. I pulled my carbs off as they were leaking as well and gave them a good cleaning with carb cleaner..there's really not much to them. My idle needles are solid, no rubber tips either. Only my floats have needles with rubber tips ( and they seal perfectly ). I was hoping that maybe something clogged up a carb a bit when the diaphram had torn, but I'm not convinced of that anymore. I worry that that gun shot backfire has caused a leak in the block somewhere. I am planning on giving it a better look in the spring as the boat is winterized. Interestingly, when I was on the lake trying to tune the carbs, adjusting them lean never really raised the idle. It seemed like all I could do with the idle jets was kill the motor.

When I ran it out of fuel and the carbs started to run lean, the idle raised up expectedly. I'm thinking that I'm flooding the motor as everytime I've pulled plugs, they are slightly wet with oil...man, and it was running so beautifully before the explosion too...