88 Force 85hp (3 cylinder). Engine sputters under heavy acceleration from idle.

[Zink357]

Honestly anything from 2-3mph at idle is average on most boats. The better the motor runs, the slower you can idle without it dying. Mine won't stay running in gear at less than 800rpm. I have a 125 on a 17' that i like to use for fishing and the slowest i can get it to idle without dying is about 2.3mph.

 

[DunbarLtd]

Honestly anything from 2-3mph at idle is average on most boats. The better the motor runs, the slower you can idle without it dying. Mine won't stay running in gear at less than 800rpm. I have a 125 on a 17' that i like to use for fishing and the slowest i can get it to idle without dying is about 2.3mph.

Yea ok this is my first boat. Thought Id buy a budget boat for my first one to minimize losses. With this 85hp I had it set when air screws were 1 turn out to idle at like 3.5mph and it seemed to do ok. Then when tying to see if opening the air screws helped with the hesitation i noticed the idle dropped way down and stalled out so i got it back to where it would run @ like 2.5mph i think. Its stalled 1 or 2 times since then so i think it may have to get bumped up again. Thanks for your input.

 

[DunbarLtd]

The factory updated the air screw setting in 89/90
They recommended 1 full turn and leave it there.
As far as speed at idle? is different on different boats.
My 21 with twins was used for trolling in the Chesapeake and the waters off Ocean City, Md.
It ran about 2.4 at the rpm setting of 750-800
Then I moved to Michigan and more trolling, slower this time.
Dropped the rpm to 600 on one motor and it ran 1.4
The bad is the motors carbon'd up pretty bad and needed re-ringed.

Sierra 20 pole tach.
Hope it shows?? If not Google 20 pole tach.
https://www.google.com/url?sa=t&rct...121896655471&usg=AOvVaw0A1yqTY8mXXNQ89IKvvuo6

Ok thanks. I found a tach and ordered it.

Now it already has a purple wire ran to the dash from the engine. But I know there are other wires needed to hook it up. I cant find anything about hooking these up. Do you know of any info out there that i could read to get it installed properly?

I did read a little about them on some other forums and some people had to mess with the pole setting to get it to read correctly but with the one i bought i read some reviews and a couple of them said they worked right out of the box.

But Im just not exactly sure what wires to use. I think one needs to be the ignition wire as well?

Plus a ground?

Im assuming the signal would be purple wire? Thanks for the help Jerry.

 

[kbh121956]

The purple wire that's under the dash goes to the tach. You will also have a black wire that is hooked up to your other gauges, that is your ground. Does the tach have a light? If it does you will want to wire it up to your light switch for night time use..

 

[DunbarLtd]

The purple wire that's under the dash goes to the tach. You will also have a black wire that is hooked up to your other gauges, that is your ground. Does the tach have a light? If it does you will want to wire it up to your light switch for night time use..

What about power so when i turn the ignition on the gauge gets power? Just splice into the other gauges power wires? Or i could even add a ring connector and wire on the gauge (fuel gauge for example) itself then run that wire to the tach?

OR what i plan to do is remove the old speedo because im using gps. I assume i could just use that power wire for the tach? Maybe even use the ground and light wire as well, then hook that purple wire to sender terminal?

Sound good or no?

 

[jerryjerry05]

Yes
You'll see the wires for powering the light and power to the gauge.
Just jumper them.

 

[DunbarLtd]

Yes
You'll see the wires for powering the light and power to the gauge.
Just jumper them.

I forgot to say but i changed out all the stock gauges. Specifically speedo, fuel and water psi. I dont know what this boat came with stock but these were all the gauges it had on it.

The "old" speedo hole is 3 3/8, which is the updated gauge I installed, and so the new tach should slip right in. Ill just use those wires and then uncap the purple that was under the dash already and use that. I redid all the wiring and connections (ring terminals) under the dash and added a new updated fuse block with double prong fuses instead of the old school ones

So Im pretty sure I can just use the same power and ground wires as the speedo? And of course the signal wire from the engine. Not sure if this tach has a light but the old speedo did so ill just use that wire for the light. I dont see any issues with doing it this way unless theres something im missing?

Off topic a little but reading through the manual i noticed the fuel pump has a spring under the diaphragm.

Is this necessary because mine does not have one????

 

[jerryjerry05]

No the spring was added sometime in 88???
My twin 88/85's ended up with both types.
Makes no difference.

 

[DunbarLtd]

No the spring was added sometime in 88???
My twin 88/85's ended up with both types.
Makes no difference.

OK good to know.

 

[DunbarLtd]

The cylinder drain screens and valve going into the intake were not obstructed. I bought new gaskets and its all back together. Going to test it out in the next couple days.

I noticed something with the prop. When its in gear and i spin it by hand there is a dead zone maybe about an inch or so each way before it stops because the drive shaft stops it since it isnt running.

Basically when it spins to a point then stops, Id have to turn the engine over to get the prop to keep spinning. So it will spin each way for a few inches until it hits this spot. Hope that makes sense.

What causes this deadzone or this normal?

https://www.youtube.com/watch?v=9ib2OkytCBs

I watched the video and i noticed the prop did not spin right away when he put it into gear. I guess that is what im feeling???

Thinking about it a little more is there a design purpose so it makes it easier going from forward to reverse? You want a deadzone there so its easier on the gears???

I havent had any issues that might indicate a spun hub on the prop. The prop is new and Ive marked the hub and it hasnt moved.

 

[DunbarLtd]

I guess its called rotational play. LOL I can get wordy at times. Sorry for the last post. Tried to delete it and start over but I cant.

How much rotational play should there be while in gear? Forward and reverse have maybe an inch of play either way.

Thanks.

 

[Nordin]

That play you talking about is just normal.
It is the distance between the clutch dog "teeth" and the "teeth" in the gears .
If you google about how a outboard LU working you will see.

The pinjong gear is always attached to the forward and reverse gear and they always rotate when the engine is running does not matter if in forward, reverse gear or neutral.

It is the clutch dog that connects the drive shaft and prop shaft and make the propeller to move.

 

[DunbarLtd]

That play you talking about is just normal.
It is the distance between the clutch dog "teeth" and the "teeth" in the gears .
If you google about how a outboard LU working you will see.

The pinjong gear is always attached to the forward and reverse gear and they always rotate when the engine is running does not matter if in forward, reverse gear or neutral.

It is the clutch dog that connects the drive shaft and prop shaft and make the propeller to move.

Went out to the lake again today. I managed to check compression. About 130ish on all 3 so im assuming thats fine.

When i stopped to do the compression test I cleaned the plugs and when i started it back up and ran across the lake i got to 33.5mph.

Its looking like it has something to do with the plugs. But i dont know because they didnt look all carboned up really. I mean one of them had some small chunks of carbon, which im sure is not normal but they werent fouled i dont think.

So for whatever reason after that run i again only saw 30mph tops when trimmed. Weird, to say the least, but I think Im narrowing it down. I can at least mark compression off the list.

One other thing that popped up that might be an issue (or not) but what is running water pressure at cruising speed on these motors? Im assuming its @ 5K rpms???

I remember getting around 15psi in the past and today i noticed cruising it was only around 9-10psi. It did bounce up into the 12 range for moments but ultimately it settled to around 9 or 10.

I took the gauge out and tested it with a known good tire gauge on my car tire. The gauge works just fine. Reads exactly what its supposed to. Tested it @ 25psi and its on the money. The hose from gauge to motor could be clogged but i blew it out so i dont think thats the isssue.

I removed the thermostat and its good to go. No blockage. Open and closes. (put it in hot water to make sure)

Either I have a gasket failing somewhere, which may explain the power loss perhaps???

Or the impeller is starting to fail???

I have an impeller kit i bought years ago but never used it. Its probably time to get in there and get it done.

Anyways, I still have that intermittent WOT speed issue.

I have a tach on the way and will know more but i feel like the water pressure is priority right now.

 

[DunbarLtd]

I inspected the exhaust plate cover or whatever its called and noticed some water deposits near the very bottom. Got a mirror and a light in there. Looks like the very bottom bolt on the cover worked itself out a couple turns. I may have figured out the water pressure loss. Not sure if that affects running performance????

So do I just tighten the bolt back up to torque or can i put anything on the bolt to help seal it? Its possible the gasket is torn but id like to try just re tightening the bolt and see how it goes. Probably need new gaskets in the future if I had to guess.

Anyway to test if that gasket has blown other that the obvious water leak? Its coming out of the bolt as far as i can tell. Which is odd because i dont think water should be inside a bolt thread.

What should I do???

 

[DunbarLtd]

Dont know what I was thinking when I wrote that last sentence. The water is obviously coming from the gasket because of the loose bolt. Of course the water is going to come from the bolt hole. Anyways I will just try and re-torque the bolt down and if it still leaks ill just do the gaskets and hopefully fix the problem as far as the leak goes.

I read some other posts and Jerry jerry said the plate warps and you have to add sealant to the gasket or they will leak again. Also talked about milling the surfaces? Did he mean the block??? Or just the cover and plate???

If anyone has done these exhaust gaskets Id like to hear your input on it. Looks pretty straight forward as far as replacement. But any helpful tips would be nice before i do it since this is my first outboard and ive no clue how these things go. I can turn a wrench on cars but these outboards are new to me.

Also I havent heard the overheat buzzer while cruising and Ive checked it and the horn sounds. Not sure if the thermal part of the sensor works but im assuming its functioning and the engine hasnt overheated yet.

Anyways thanks for the help. If this water leak repair doesnt fix the main power loss problem I will concede and live with the issue and end this thread.

 

[jerryjerry05]

Just add some sealer/ sillycone to the bolt.
You might need a washer to make it seal??

Motors with a lot of use and long time use in salt water the cover and the block gets corrosion and
milling both surfaces really helps make a seal.
The edges get eaten away making it harder to seal.

You can test the sending unit with an ohms meter.
Remove,put in pot and slowly bring up the temp

 

[tg3690]

Dont know what I was thinking when I wrote that last sentence. The water is obviously coming from the gasket because of the loose bolt. Of course the water is going to come from the bolt hole. Anyways I will just try and re-torque the bolt down and if it still leaks ill just do the gaskets and hopefully fix the problem as far as the leak goes.

I read some other posts and Jerry jerry said the plate warps and you have to add sealant to the gasket or they will leak again. Also talked about milling the surfaces? Did he mean the block??? Or just the cover and plate???

If anyone has done these exhaust gaskets Id like to hear your input on it. Looks pretty straight forward as far as replacement. But any helpful tips would be nice before i do it since this is my first outboard and ive no clue how these things go. I can turn a wrench on cars but these outboards are new to me.

Also I havent heard the overheat buzzer while cruising and Ive checked it and the horn sounds. Not sure if the thermal part of the sensor works but im assuming its functioning and the engine hasnt overheated yet.

Anyways thanks for the help. If this water leak repair doesnt fix the main power loss problem I will concede and live with the issue and end this thread.

Recently had to replace my exhaust port cover. It had corroded badly from the inside out near the bottom, probably near that same bolt you were talking about. If it is the same bolt, I found that out of the 20 bolts that hold that cover on it is the only one that protrudes into the exhaust stream. The rest are screwed into the block. This bolt was very corroded and was difficult to get out. The reason this cover never leaked before is because I found the bypass valve was completely gunked up and was not allowing water to enter the exhaust cover at all. Not good. So I had to literally dig the spring and plastic valve out to allow water to flow. Decided to leave the bypass valve and spring out and put back together. When I tested the engine, water was spraying out of the cover itself. Found a new cover and 2-gaskets on Ebay. I used Permatex Optimum Gray sealant on the exhaust plate gaskets. Supposed to be a very high temp sealer good to 700 degrees. The old exhaust plate cleaned up well using a scotch brite pad and solvent. When reassembling I coated both sides of both gaskets with the optimum grey and used anti seize on the bolts. Torqued to specs and no leaks. I had asked JerryJerry about the bypass valve. He said it was not really needed and to use a thermostat.

 

[DunbarLtd]

OK I will look into the bypass valve. Sounds like the same issue going on. Ill try the silicone on the bolt and see what happens. Then poke around and see about getting some gaskets as Im sure it needs them. Late 80s prob never been changed. Actually pretty impressive its gone this long without them changed. The bolts look untouched so im sure its oem gaskets in there. Anyways thanks for sharing. Wish me luck!

 

[tg3690]

BTW....If you find that you need new bypass parts, I have the gasket, spring, and valve that I bought and never used.
Bypass valve gasket #27-F85762 Bypass valve spring #24-F404268 Bypass valve #20-F85916-1 These parts should fit your motor. Let me know if you need them.

 

[DunbarLtd]

BTW....If you find that you need new bypass parts, I have the gasket, spring, and valve that I bought and never used.
Bypass valve gasket #27-F85762 Bypass valve spring #24-F404268 Bypass valve #20-F85916-1 These parts should fit your motor. Let me know if you need them.

Thank you sir. I might need them. I'll take a look tonight and see whats going on in there.