85 hp force has no power and stalls

Hazzard

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Jun 21, 2017
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I have a 1989 bayliner Capri I\o with 85 hp force engine. The boat will backfire out of the exhaust when starting but seems to run and start fine when it warms up on the muffs. When I give it throttle it stutters a bit before it will rev up. When I'm on the lake it starts and runs fine until I put it in gear and hit the throttle. It just won't plane out and seems to have no power. Keep in mind this was the first time I took it out since winter. Last year it would at least plane out with some stuttering but this year she really won't pick up speed. There is spark and good compression. Wondering what could be the cause of it not revving up. Put sea foam threw before winterizing and just checked the screen from fuel tank. Any help would be great!! Thanks
 

Jiggz

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Oct 23, 2009
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Can you post the compression numbers? Also have you tried dropping cylinder ( pulling plug cable one at a time while idling) to find out if there is change in engine rpm? What does the plugs look like?
 

jerryjerry05

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May 7, 2008
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Backfiring: sucking air somewhere? reeds? carbs dirty? low compression? water in the fuel? air screws set wrong?

Do a comp test and post the results an do a spark test post results.
 

Hazzard

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For some reason I can not find the gauge for compression tester but last time I checked it was over 120 each cylinder. All plugs are getting spark but when I pull top plug wire while running it does not effect idle. Plugs are wet when I pull them after running. Cleaned carbs and did link and synch last year thinking that was the reason for the stutter but it had no effect. Put fuel treatment in after fresh gas so I don't think water would be the cause.
 

Simple_Man

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If you have an on board fuel tank check for water. Even a little bit can cause a stutter.
 

Jiggz

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If dropping cylinder #1 doesn't change idle rpm, that means #1 cylinder is not firing. And you attest there is spark on all spark plugs and that compression is good, above 120 PSI on all three. Then the only cause would be either #1 carb is not feeding fuel or you have damage reeds.

Next troubleshooting would be to spray fuel oil mix directly to the #1 carb while idling and listen for change in engine rpm. If there is no change it means, reeds are most likely damaged. Or if there is change or increase in rpm, then there is carburetion problem.
 

jerryjerry05

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Check the reeds.
I think most auto parts stores loan tools.
Just remember they are usually cheap and abused so the results can be drastically different.
Compression can change from one day to the next?

​Fuel treatment only gets rid of a tiny bit of water.
Simple man had 20 gal of water. No treatment is gonna help that.

Unhook the fuel line at the pump.
Squeeze the ball and direct it into a clear glass jar.
Then let it set for 5 min.
​That will show the water if there is any.

​I use a water separating filter between the tank and the squeezie.
I change it yearly.

If the boat sets for any length of time?
​Condensation.
​Ethanol seems to draw water??
 

Hazzard

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Ok, a little update. After a long search of the gauge for the compression tester, I tested each cylinder. All were over 120, about 125. So it's getting spark and has compression. Started her up and sprayed gas mix in each cylinder. #1 top stuttered them idles higher for a second. #2 middle and #3 bottom had small stutter then idle dropped. On to pulling carb and cleaning.
 

Hazzard

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Jun 21, 2017
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Pulled #1 carb and it had a little bit of sediment in the bowl. Pulled everything and blew it out with compressed air. Put it all back together and not change. Pulled the fuel line to get a sample of fuel to see if water is in it and seen nothing. Put it back together then ran it again. Pulled #1 plug wire and it is now responding. Not sure what I did when pulling fuel line but it seems to be running on now. Still has a little stutter and idle isn't the best but seems to rev up fine now. I will have to test it on the lake tomorrow but so far so good! Not sure what the stutter is. Maybe just needs a tune. Will update After lake test.
 

Jiggz

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The next step is to tune the fuel air mixture screw. If you are not sure what this is, post and let us know. But it should be initially set to 1 turn out from seated. Again, if you're not sure what this means, post. Usually, this screw is best set to 1 ~ 1 1/4 turn out from seated.
 

pete j

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Nov 21, 2012
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I was suffering the same problem as you are now. mine turned out to be the little green rubber thing that the float needle rests against. It was smashed flat and no fuel could get to carb. Dont know if your carbs have the same rubber thing as my 86 force 85 but if it does it would be a thing id check.
 

jerryjerry05

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That's seal in the seat gets damaged by ethanol and fuel additives like seafoam and carb soaks.

​To see if the carb needle/seat is ok? Pump the ball until firm.
Then loosen the top float bowl screw.
Fuel should drain out.
Do this twice.

There are 2 types of needle/seats.
​The other has a rubber tip on the needle, it also can get deformed from chemicals.
 

Hazzard

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Jun 21, 2017
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So I've checked and cleaned the #1 carb and it is getting fuel. The bowl fills up and the needle seats good. Everything seems fine as far as fuel, spark and compression. When I rev the engine up and pull the plug wire for the #1 cylinder it does nothing. When it's idling and I pull the #1 plug wire it sputters like the #2 and #3 do when pulled. Seems to be weak or intermittent spark on #1 only when revving up. Not sure what to test from this point. Would getting spark on #1 rule out coils and CD box? Would a bad rectifier cause this issue? It ran good before overheating and melting #1 cylinder so I swapped the engine out for another. I reused everything from the blown engine except the trigger and stator. My thoughts are it could be bad stator or trigger from New engine. I do not have a dva meter or know what wires to test. I have volt/ohm meter but no troubleshooting guild online gives me the right color wires to test. A walk through would be so help full right now!
 

jerryjerry05

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What's the compression readings?
The trigger has tiny lead that break under the shrink wrap.
​They look good and solid.
Try pulling the wire and see if it comes apart.
I replace the connectors as SOP when I have an electrical problem.

Try moving the 2 top coils around?
Then try moving the packs around to see if the problem follows the swap.
 

Hazzard

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Jun 21, 2017
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Ok, I got around to trying to swap packs but couldn't keep it running long enough to see if that was the problem. While I was swapping them back both wires for the #1 cylinder, from pack to buss bar, came out of the connector. I hooked it back up then tried it again and still idling rough. I tugged on wires going to the back of stator and it idled good again. I pulled it from the buss bar and the connector started to smoke. Sure enough there was a THIRD connector that came apart. Hooked that back up and it seems to be running smooth again. When I rev it up and pull the #1 plug it will respond. Looks like I'll have to try to get her out on the lake this weekend and see if she will plane out now. I've tugged on those wires so many times and rechecked them just as many times and never noticed the wire being loose in the connector. I'll have to check back but so much thanks to everyone who has helped me this far. You guys are great! Thank you
 

jerryjerry05

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Change ALL the connectors.
It's a pain but can solve future problems.

Oh yea do ONE at a time!!

​The ID tags on the leads are probably gone by now??
Replace them as you go.
 
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