1992 Force 70 Runs Slow with cover on fast with it off

[themtimes]

My Force 70 outboard was bogging down bad less than 10 mph at full speed. I took the cover off the motor and it immediately got up to 35 mph. Put the cover back on and 10 mph again.

I took the boat it to get the carb cleaned and new plugs. Got it back out on the water and the same thing.

Can anyone help me get this thing up to speed with the cover on? I am currently on vacation with the boat and not having any fun. Thanks

 

[bentle]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

Right on the back top of your upper cowl cover there is an opening to let air into the engine
Compartment. Make sure this is open so that the air is free to get through the small space up
under the handle.

 

[themtimes]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

I assume the Cowl is the Cover itself that I can take on and off? If so it's clear of everything including the insulation I cleaned everything out.

 

[bentle]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

Yes that is correct. It is the cover that you can remove. Reason I suggested it was because on my
force outboard I decided to stuff a plastic bag up in mine and forgot to remove it before the lake
when I got going it did the same thing.

 

[roscoe]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

Could there be a wire, that is getting moved/bent/pinched, when the cover is on?
An ignition wire that is cracked, and shorts when the cover is on?




More than likely you have an exhaust leak, leaking into the cowl area, choking out the motor.

Its not something you are going fix while on vacation, so either park the boat or use it with the cover off.

 

[themtimes]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

Is it okay to run the boat with the cowl off if it is an exhaust leak?

 

[roscoe]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

As long as the electrics stay reasonable dry.

Don't run it in the rain and don't play wake jumper.

And make sure everyone stays away from the spinning flywheel.

 

[bentle]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

That was going to be next suggestion. Great job on that.
The exhaust leak. Wondering though, couldn't he check and see if the rubber boot has fallen
or slipped off the pee hole inside the lower cowl, then put it back on?

 

[themtimes]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

Bentle, can you describe where that rubber boot is or what else I can look for as far as the exhaust leak? Thanks again guys!

 

[themtimes]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

I think I found the cause. Theres a plate that it looks like the motor sits on (spacer plate). That plate is cracked in the back and exhaust is coming through there. This one is going to hurt isn't it?

 

[roscoe]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

New spacer plate is $400.

Top and bottom gasket, $20 and $40.

Perhaps the spacer plate can be welded.

If it is all secure, you could just clean it up, scuff up the metal, and use a 2 part putty type epoxy to plug it up.
Something like JB Weld.

Kind of redneck, but it should work, and save a bunch of dough.

Then watch ebay for a replacement.
They usually go for pretty cheap. One on there now for a 50hp, won't fit your motor, but under $25.

 

[themtimes]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

I've attempted the JB Weld and it's vibrating a bit much. I have to get another bolt into it and scuff it up and try it again. Whats with the gaskets? Do I need those too?

Will it hurt anything to run the boat with the Spacer Plate cracked? The guy at the marina said the motor itself is clear from anything being damaged
it's just the exhaust bogging down the motor when the cover is on.

 

[roscoe]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

Don't think you have to worry about damaging anything, as long as the powerhead is secure and not moving.



If and when you replace the adaptor plate, you should replace the gaskets, or reuse the old ones if not damaged.

All you need to do for now, is plug the hole.

Perhaps even a spray can of expanding foam. Don't spray it into the hole, just over the top to seal it.

 

[fucawi]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

or you could make a vent in front of the carb to let the air straight in ....

 

[bashr52]

Re: 1992 Force 70 Runs Slow with cover on fast with it off

I've attempted the JB Weld and it's vibrating a bit much. I have to get another bolt into it and scuff it up and try it again. Whats with the gaskets? Do I need those too?

Will it hurt anything to run the boat with the Spacer Plate cracked? The guy at the marina said the motor itself is clear from anything being damaged
it's just the exhaust bogging down the motor when the cover is on.

Are you trying to JB weld it while the engine is running?