Force 90 only starts with starter fluid in cylinders

[FJH]

Greetings all.

I've been reviewing several posts using the search feature before actually posting. I could find related posts, but not the exact match. Here's my issue, and your advice will be sincerely appreciated:

I bought a boat a week ago with a Force 1990 90 HP 3 cylinder 2 stroke engine. Initially, the seller showed me to start it by pulling the cowl off, manually choking, and cranking. (The electronic choke is missing since some shop visit in the past before my ownership.) This method did seem to work the first time (of 3) I took the boat out. After warm-up, no need to manually choke, just use the push button on the console.

The boat died when put into gear, but can be started in gear, and runs like a top. Ran WOT for 2-3 hours.

2nd trip out (2 days later), same starting method but required additional throttling manually while in neutral. Same issue shifting gears. Ran like a top at low speeds and planing WOT.

Service Day (Last Friday) I replaced the priming bulb, pulled and inspected the plugs. Started (with muffs) with the manual choke manipulation and manual throttling. Once warmed up, engine went into forward and reverse with no issue. Problem solved?

Trip 3: Would not crank. Repeat, would not crank. Finally cranked after replacing plugs, new battery, and juicing starting fluid directly into the cylinders and manually revving the throttle in neutral. (I've since read this is a bad thing to do.) Dropped the boat into the water, same process, I revved her up as she was put in gear, then we ran her for around 4 hours, WOT and slower. My buddy jumped in the water to cool off, so I putted around. Engine died, but with throttle in gear and immediate pushing of the start button, she came back to life. Same thing back at the dock.

Some additional info: Previous owner (who of course never had these problems) used the Stabil treatment in the tank. West Marine says "no" to this and offers a different treatment, which I put in yesterday. I have run through around 40+ gallons in these 3 trips. I should have flushed old gas by now. Previous owner also said he took her out a few days before selling. Said he was selling for financial reasons.

Yesterday, I verified fuel flow was strong and the fuel intake side of cards. I also pulled off the intake vent and visually inspected the air intake ports. They looked clean to me.

I've only ever worked on 4 stroke engines, so I don't understand the cards. I do have a Clymers manual. I suspect my problem is in the carbs. Do I need to buy rebuild kits, or can I just disassemble them clean, and re-install them?

Thank you again for your time.

FJH

 

[roscoe]

Re: Force 90 only starts with starter fluid in cylinders

Welcome to iboats FJH.

Before toughing the carbs-throttle or timing linkage, read the manual.

First issue to repair, is that it will start while in gear.
It should never start while in gear.
The neutral safety switch needs to be repaired.

Second, do not use starting fluid.
Use premixed fuel if you need to, for testing.

Third, find a source for SeaFoam, get a couple cans and use it regularly.

Basic background of engine condition is needed. do a compression test, and check the strength of the spark on all 3 cylinders.

How did the sparkplugs look? water? oily? dry?
black residue? black caked on carbon?

Next, what is your idle speed in neutral? And in forward gear?

How many rpm's at WOT ?

What year is the motor?

 

[FJH]

Re: Force 90 only starts with starter fluid in cylinders

roscoe,

Thank you for your prompt response. I'll answer your questions in reverse;

The engine is a 1990.

I can't tell you about the idle rate, as there is no tachometer. The only electronics with the boat was a fuel gauge, which is dubious at this point in its accuracy.

I did add a depth sounder, but haven't gotten around to the tach yet. I think it idles at around 650, which I've read is the minimum for this motor.

Plugs were changed yesterday. I pulled them on Friday. They were black, but not glazed, caked, etc. Also, before I coaxed a crank yesterday, an old salt took out the top plug, and we grounded it to the engine. When we cranked her, his eyes lit up!

Either way, there are brand new plugs which safely (maybe?) carried us around an island in the ocean, then back to home port. I really feel the issue is carb related, but may be in the fuel tank, since this only happens when I fill her up. I tried venting the tank through the fill spout as well.

Sea Foam: I'll consult Google and take your advice.

I understand the negatives of using starting fluid now, but didn't at the time. I'll do better.

As for the neutral start switch, until I can get her to properly run at idle and move through the gears, I'm gonna just monitor this one manually.

Lastly, I have the manual. I've read the chapter on the carbs (chapter 6 in the Clymens).

Now for the rest of the story:

I cranked her today and got her to run reasonably well by first loosening the idle set screws on the carbs, which made her run rough, then I put them back to the original position, and she ran great if I manually adjusted the throttle. I found the set bushing which sets the throttle speed. I found that just a few wraps of electrical tape (just handy at the time) stepped up the RPMs enough to keep her running smoothly at idle and cycle through the gears. Problem solved?

Trip 4: Didn't happen. I gassed her up, and that, apart from the commute to the dock (5 miles max) was the only variable altered since the crank-up at home. She cranked beautifully, backed off the trailer, went into forward, and as my companion was idling around waiting for me to park the trailer, the engine died. We have some strong currents in this area, resulting in a tragically comical event of the boat washing into some remote sea walls. I hitched a ride to our boat, and pushed her off the sea wall. I love barnacles! Anyway, we got a tow back to the warf, and put her on the trailer.

So, any advice?

 

[jerryjerry05]

Re: Force 90 only starts with starter fluid in cylinders

Get the tools to check the spark and compression.Just lighting up the girlfriends eyes is fun but not the real test.To diagnose any problem you need to check:comp/spark/fuel.
Check the fuel pump diaphram.
Check for water in the filter(you have a filter?)no put one in.J

 

[FJH]

Re: Force 90 only starts with starter fluid in cylinders

Duely noted...I will continue with the testing and report results. Some things have changed;

I pulled the carb module (3 carbs attached to the intake manifold) and cleaned them. I also reset the idle screws to manual spec. The boat cranks fine and runs great now...on dry land. Now she won't crank cold in the water.

Just took her to the landing, and once in the water on the trailer she won't crank. I pulled the trailer out of the water and cranked her dry. She started great. Didn't die or anything. We took her out for an hour, and when back at the marina, she idled great as well. For the first time ever, she was actually motored onto the trailer.

I don't know why she wouldn't start in the water. She started fine on dry land. The boat landing is only 5 miles or less from my house.

As always, thank you for your advise.

FJH

 

[roscoe]

Re: Force 90 only starts with starter fluid in cylinders

roscoe,

Thank you for your prompt response. I'll answer your questions in reverse;

The engine is a 1990.
Ok, so it has a conventional choke, ( newer model had an enrichment valve)

I can't tell you about the idle rate, as there is no tachometer. The only electronics with the boat was a fuel gauge, which is dubious at this point in its accuracy.

I did add a depth sounder, but haven't gotten around to the tach yet. I think it idles at around 650, which I've read is the minimum for this motor.
You probably need 800 in forward gear, 100 in neutral.

Plugs were changed yesterday. I pulled them on Friday. They were black, but not glazed, caked, etc. Also, before I coaxed a crank yesterday, an old salt took out the top plug, and we grounded it to the engine. When we cranked her, his eyes lit up!
Sounds good, but you need to check all three plugs to verify they are all working.


Either way, there are brand new plugs which safely (maybe?) carried us around an island in the ocean, then back to home port. I really feel the issue is carb related, but may be in the fuel tank, since this only happens when I fill her up. I tried venting the tank through the fill spout as well.

Sea Foam: I'll consult Google and take your advice.
SeaFoam is great stuff for stabilizing your fuel, keeping the fuel system clean, keeping carbon from building up throughout the engine, it even frees up stuck rings sometimes.
For your reading pleasure:

Decarbing is a 2 part process. The first part is preventative, done by using a fuel additive to prevent carbon build up. SeaFoam is one such fuel additive and can be found at most auto parts stores. It also works as a fuel system cleaner and should be used as a preventative maintenance procedure.If Your intent is to REMOVE the existing carbon buildup from the cylinders, heads, and rings, a spray decarb solvent product, such as SeaFoam Deep Creep, Power Tune, or Ring Free, is needed to do the decarb process. Free moving rings are what seals your cylinders and gives you compression. Compressed and stuck rings means loss of compression, broken rings, damaged pistons and heads, and eventually, engine failure.Run engine at fast idle, with engine running and warm, slowly spray liberal amount into each carb. Its gonna smoke up the place. Spray for a couple minutes, now spray a larger amount into the carb(s) until engine chokes out and stops.Remove spark plugs and spray the decarb product liberally into each cylinder, install the spark plugs, let it soak for an hour or more. Start the engine and run at medium throttle, or if at the lake, run it at full throttle. It won't hurt to spray some more through the carbs. Run it for atleast 10 minutes to flush the crud out of your engine. Now remove and clean, or replace the spark plugs. It works well to do the spraying, the night before you go to the lake. This way you can let it soak overnight, and run at full throttle at the lake.Don't do this in front of the garage door or the house, unless you want it covered with greasy black crud.************************************************* ***********The following was posted by Dhadley, member #685. It explains the need for doing a decarb as part of your regular maintenance.""As for the carbon or coking, it all has to do with combustion temps and load in a 2 stroke outboard. We're not talking engine temps, but rather combustion temps. We're talking about an outboard, not a motor with very low and consistant exhaust restrictions like a motorcycle or a snowmobile or even a car.We're also talking about an engine that is always under a strain. Unlike a motorcycle or snowmobile or a car. An outboard must take off in high gear. Unlike other vehicles that have transmission that keep the motor "happy". Try that with your car. Outboards never coast. Would your car like that?Thru the years as the fuel changed we have seen this coking problem (carbon build up) get worse and then a bit better. It really seemed to help when the EPA removed MTBE from the fuel.Anyway, heres the results of some testing we did for OMC back in the mid 80's or so. It remains constant today.We used a V4 crossflow on a 16' boat. For the first part we loaded the motor up heavily -- dropped the X dimension and used a prop that would only allow a top rpm of 4800 with 2 people on board and 18 gal of gas. When it got light on fuel and only one person it would still only get to about 5200. Extreme? Yes, but it happens. Look on this board how many folks talk about their set up being close to this. At the time OMC was recommending that Engine Tune be used every 50 hours. We were still seeing coked up pistons and broken rings. On our test motor we coked up the pistons (starboard bank) in 12 hours of running. We broke rings at 19 1/2 hours. We rebuilt the motor and set it up on the same boat to turn 5800 with 2 people and 18 gal of fuel. We used no Engine Tune, no Carbon Guard or additives of any kind. Just OMC TCW II (I know, it was old school but thats what they wanted). After 500 hours there were no stuck rings or carbon issues of any kind. In both parts we ran the boat just as a pleasure boat. Cruising, idling, running flat out -- nothing special. The carbs were always clean, the water pressure was always correct, Champion plugs were always used as well as fresh 87 octane fuel.Now, if you look at combustion temps with that motor, the temps were much higher in the first test than the second test. High combustion temps promote coking. Coking leads to stuck rings. Eventually the rings break (more correctly the end is sheared off as the piston losses support).Hope that helps some.""************************************************* **********And this was added by DJ, member 5471.""Outboards are probably the most abused engines ever. An incorrectly propped engine is the norm, not the exception. That incorrect propping results in carbon build up. It has nothing to do with lead.Think about it. Some folks dole around at trolling speeds or non-planing speeds for hours. That leads to serious deposit build up. Add oil in the fuel and you get the problem described.Engines that run at high speeds for most of their lives may never have the issue.However, a decarb does NOT hurt anything, except maybe the plugs, and is a good preventive maintenance practice.BTW, the decarb. process has nothing to do with gunked up carburetors. That's a fuel storage issue best dealt with using fuel stabilizers.""
_____



I understand the negatives of using starting fluid now, but didn't at the time. I'll do better.

As for the neutral start switch, until I can get her to properly run at idle and move through the gears, I'm gonna just monitor this one manually.

Lastly, I have the manual. I've read the chapter on the carbs (chapter 6 in the Clymens).

Now for the rest of the story:

I cranked her today and got her to run reasonably well by first loosening the idle set screws on the carbs, which made her run rough, then I put them back to the original position, and she ran great if I manually adjusted the throttle. I found the set bushing which sets the throttle speed. I found that just a few wraps of electrical tape (just handy at the time) stepped up the RPMs enough to keep her running smoothly at idle and cycle through the gears. Problem solved?

Trip 4: Didn't happen. I gassed her up, and that, apart from the commute to the dock (5 miles max) was the only variable altered since the crank-up at home. She cranked beautifully, backed off the trailer, went into forward, and as my companion was idling around waiting for me to park the trailer, the engine died. We have some strong currents in this area, resulting in a tragically comical event of the boat washing into some remote sea walls. I hitched a ride to our boat, and pushed her off the sea wall. I love barnacles! Anyway, we got a tow back to the warf, and put her on the trailer.

So, any advice?

Probably a good idea to rebuild the carbs, and perform a linc n sync.
Your Clymer manual does a pretty good job of walking you thru it.

 

[FJH]

Re: Force 90 only starts with starter fluid in cylinders

So I am following up with your advice.

I don't have the tools to do a compression test or proper spark test, so I took the boat to a mechanic located next to one of my customers.

He said the compression was good. (All cylinders over 120, close to each other.)

He said spark was good. He then soaked the carbs, cleaned them, conducted a link and synch, hooked up a choke solenoid (used - they tell me you can't get a new one any more.), and wired it to a key switch which I provided. He is going to replace the throttle cables, but wanted me to have the boat for the weekend.

She cranked and ran great.

I did have a calamity, but I"ve chosen to start a new thread related to this issue, as I feel it is unrelated.

Thank you all for your advice. You pointed me in the right direction, which was to have a compression/spark test performed. I happened to find a good mechanic, and although I typically fix my own stuff, I think I will have use for him in the future.

By the way, his shop is Master Tech in Charleston, SC. he is very honest and knowledgeable.

 

[jerryjerry05]

Re: Force 90 only starts with starter fluid in cylinders

Glad you found someone who you trust.There are lots of people who talk a good story.But few actually do good.J