1990 Force 90hp 3 cylinder won't start ughh

[MayTheForceStreeMeOut]

I'll start off my saying I have looked all over the internet for ideas on what's wrong here and I can't figure it out... I bought this 1990 bass scaler with 1990 Force 90hp and was just told it needed a new trim motor. I bought it off a retired Sgt. of mine so I took his word. Well the new trim motor didn't work so it's probably needs a new trim relay or solenoid or hydraulic pump but I said I'm going to make sure it starts before I spend the cash for those. So I got new plugs and put new gas in it...and the starter doesn't engage the flywheel enough to start. Next I bought a new starter solenoid and same thing, then I bought a new starter and charged the battery this made it spin the flywheel more but not enough to start it. I bought a compression gauge but it's with the engine cold but it's 60 psi on all 3 cyclinders. I also took off the the fuel lines to see if the plastic lining was coming off and couldn't find any blockages so I tightened everything back up and cleaned the battery connections and put new terminals on the cables. I just have no clue what to do next??? Take off the carb and clean it ? My battery says it's 12.74 when hooked up to a multimeter, should I run it off a little portable tank to rule out a dirty fuel tank? I drained the tank as much as I could and put a couple gallons of a new mixture in it. Any help is appreciated

 

[Nordin]

You need to check if it has spark at all three plugs.
60 PSI compression is way to low but as you says it has 60 PSI at all cylinders it might be the gauge that shows to low numbers or you have not spin it over long enough. The good thing is that all three are even.
The compression should be 145-150 PSI or at least 120 PSI to run decent.
An engine need three basic things to run. Compression, fuel and spark.
Start from there and then we can go further.

 

[puffitu]

As Nordin mentioned; 60 compression is way low. Verify the comp-maybe the gasket is shot

 

[jerryjerry05]

Is it a Harbor Freight tester? That's why it's low.
BUT!!! at 60# on all 3 that shows the cylinders are
probably ok , and you just need a better gauge.
You didn't mention spark???? You test for spark?
At any auto parts store they sell spark testers.
Using the key to turn the motor over without
grounding the plug wires can damage the packs.
Get a new comp tester, and do a spark test and
get back with the results.
After the spark, comp tests, check the oil in the lower
unit for water, any water can cause the gear box to
drag and make the motor turn over slow.
There's a slotted screw on the front of the gear case,
DONT remove that screw to drain the oil or check the
oil. The drain plug is on the bottom and might be an
allen headed set screw.
If there's water? remove the lower and see if the motor
turn's over easier??
Load test the battery?? You can have a dead cell?

 

[MayTheForceStreeMeOut]

You need to check if it has spark at all three plugs.
60 PSI compression is way to low but as you says it has 60 PSI at all cylinders it might be the gauge that shows to low numbers or you have not spin it over long enough. The good thing is that all three are even.
The compression should be 145-150 PSI or at least 120 PSI to run decent.
An engine need three basic things to run. Compression, fuel and spark.
Start from there and then we can go further.

You need to check if it has spark at all three plugs.
60 PSI compression is way to low but as you says it has 60 PSI at all cylinders it might be the gauge that shows to low numbers or you have not spin it over long enough. The good thing is that all three are even.
The compression should be 145-150 PSI or at least 120 PSI to run decent.
An engine need three basic things to run. Compression, fuel and spark.
Start from there and then we can go further.

Yup just got back from getting a spark tester and no spark on all 3 cylinders, good it be because the starter isn't engaging the flywheel enough? Thanks for your guys quick responses

 

[MayTheForceStreeMeOut]

Is it a Harbor Freight tester? That's why it's low.
BUT!!! at 60# on all 3 that shows the cylinders are
probably ok , and you just need a better gauge.
You didn't mention spark???? You test for spark?
At any auto parts store they sell spark testers.
Using the key to turn the motor over without
grounding the plug wires can damage the packs.
Get a new comp tester, and do a spark test and
get back with the results.
After the spark, comp tests, check the oil in the lower
unit for water, any water can cause the gear box to
drag and make the motor turn over slow.
There's a slotted screw on the front of the gear case,
DONT remove that screw to drain the oil or check the
oil. The drain plug is on the bottom and might be an
allen headed set screw.
If there's water? remove the lower and see if the motor
turn's over easier??
Load test the battery?? You can have a dead cell?

No I got the compression tester from advanced auto, I planned on changing the lower oil today, just haven't went to get supplies yet, I just tested for spark ( I did get the spark tester at harbor freight lol) but no spark on any 3 cylinders, thr tester was loose where it connects to the plugs on the motor. The spark tester did work on my snowblower so I don't think the tester is bad

 

[MayTheForceStreeMeOut]

Is the compression low just because the engine is cold?

 

[Redbarron%%]

You may have a bad CDI box or if the starter is dragging you are not getting to coming in speed for the magnetos. It has to turn about 300 RPM to reliably start.
Have you checked the voltages?
Google Force ignition testing for some good guide lines.
If you hear a dragging sound from the flywheel your magnets may have come unglued as well. This is fairly common on these old engines.

 

[MayTheForceStreeMeOut]

UPDATE: I used my other battery that's for the trolling motor after I charged it to 100% and the engine turns off great! I did another compression test and all cylinders are between 115 - 120 (better than 60 lol) but again it's just not getting a spark and firing.

Ps. I also ran the fuel lines to a portable tank and got the air out of the lines, new gas and oil mix as well because I'm sure the tank hasn't been cleaned since 1990 lol

 

[jerryjerry05]

If you have no spark then look into that?
You have a boat or just the motor?
Boat: look for the kill switch?
outboardignitiondotcom has test procedures.

 

[MayTheForceStreeMeOut]

If you have no spark then look into that?
You have a boat or just the motor?
Boat: look for the kill switch?
outboardignitiondotcom has test procedures.

1990 glassport bass scaler, it has the kill switch but it's not the original lanyard ( I read that some are universal and some are not but couldn't find what one I needed, it's a US marine throttle control)
Is there a way to bypass the kill switch?

 

[jerryjerry05]

That lanyard looks like it works???
When the kill switch is working, it completes
a circuit.
You'll have to remove the KS and tie the wire ends
together.
Like I said it might be working??

 

[MayTheForceStreeMeOut]

That lanyard looks like it works???
When the kill switch is working, it completes
a circuit.
You'll have to remove the KS and tie the wire ends
together.
Like I said it might be working??

Yeah I'm just not sure because I've seen other kill switches with different ends. I'll try to open the throttle and tie those wires together and see if it sparks after that. I looked up the testing procedures you provided via the link. I'm going to try those tomorrow, I just have to research where all the different things are on motor (its my first boat)

 

[Nordin]

I think that jerrjerry is wrong in this case about the kill switch circuit.
If the engine has the Prestolite ignition system (my sons 1988 85Hp has it and in 1990-91 they started to switch over to Mercury style ignition system) three blue or black ignition coils and two blue or black CDI boxes the kill circuit is grounding out the CDI boxes.
The key switch has two M terminals that closes together when killing the engine. One wire at M terminal goes to the CDI boxes and the other M terminal wire goes to engine ground.
The lanyard circuit is parallell with the key switch.
My suggestion is to disconnect the wires at lanyard and also the wires at the M terminal at key switch and just leave them unconnected, then check for spark.

 

[jerryjerry05]

Your right, i could be wrong??
I was wrong once but then I was mistaken
Or was I ???

 

[MayTheForceStreeMeOut]

I think that jerrjerry is wrong in this case about the kill switch circuit.
If the engine has the Prestolite ignition system (my sons 1988 85Hp has it and in 1990-91 they started to switch over to Mercury style ignition system) three blue or black ignition coils and two blue or black CDI boxes the kill circuit is grounding out the CDI boxes.
The key switch has two M terminals that closes together when killing the engine. One wire at M terminal goes to the CDI boxes and the other M terminal wire goes to engine ground.
The lanyard circuit is parallell with the key switch.
My suggestion is to disconnect the wires at lanyard and also the wires at the M terminal at key switch and just leave them unconnected, then check for spark.

This might be a stupid question but what and where exactly is the M terminal ? And yes what you described is what I have. Thank you guys for the help you have no idea how much I appreciate it

 

[Nordin]

The key switch in the remote control box has six terminals.
Two of them have a the letter M as mark, the other are S, C , I (or A) and B.
B...power (12VDC)
C...choke
S...start
I...ignition (in some set up or 12VDC in running position to feed auxiliary objects in some set ups)
In your set up the I terminal is not in use for the ignition system.
M(x2)...stop

 

[MayTheForceStreeMeOut]

You're a wizard lol I bought a pack of kill switches to see if mine was a different one but they didn't work. I tried to take off the throttle box real quick but the screws weren't coming off the boat so I'll have to get to it tomorrow (my wife wanted to spend time together on her birthday lmao). If that doesn't work should I order a new ignition coils or cdi boxes first? Be back tomorrow with updates

 

[puffitu]

Happy wife happy life..

 

[pnwboat]

Before you do anything you should first do some basic trouble-shooting. The coils do not fail very often. The CDI units run in the $300+ range. Are you familiar with using a multi-meter? Basic resistance and voltage measurements?