1998 75 HP Force. Misses, stalls hard to start. UPDATE!!

[kywings]

Been nosing around looking for solutions but need to start my own thread. I have a 98 75 force on a 25' Crest pontoon. I have had it for a year. This boat has been on the same lake and in the water year round from what I can tell its whole life. To start it up the throttle needs to be opened full, crank a lot and when it starts pull throttle back. At idle it has a hard miss. And I mean hard, 50% of the time it will cause a stall. When docking you need to do it quick switching from reverse to forward will cause a miss and stall. Then need to pump the primer to restart. Always ran good at higher speeds and 2 weeks ago I even pulled my grand kids on a tube. It stalled every time we switched riders. Primed again and restarted. A week ago at high speeds it started to die and at slow speeds it stalled. what I have done so far.

-New plugs Champion QL76V- No change. Old plugs looked good and seemed to be alll firing the same.

- Ran Seafoam through a whole tank. Before I did the primer bulb never got hard and fuel would pour from the carb. Now the primer gets somewhat hard and only a little fuel will drip from a small hole on the side of the carb when primed. Did not seem to change running issues though.

-Rebuilt fuel pump. Yesterday. Found a bad check valve and leaking diaphragm and changed fuel filter (generic inline from NAPA). Starting improved but not great. But idled with no miss or stalling. Ran so good I let it idle for 5 min and just sat and watched. As soon I tilted the motor down to take it out on the lake it started missing and stalling again. Under load it kept stalling. I put the old filter back on now it stays running, also found a loose vacuum fitting on the motor and resealed it. Now it runs good at high speeds but stalls and misses at idle.... again. Thinking of trying the Sticky and tune the carb today.

Any thoughts appreciated!

 

[TwoFish]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

Fixing the fuel pump will definitely help.

Interesting that the filter made things worse. Make sure all connections are tight so no air is getting in. The inline filter I am running is a mercury style( about 3 -4 inches long, white). It has a relatively large surface area on the filter so less likely to restrict fuel.

The fuel coming out of your carbie when you prime it means the needle and seat are not seeling properly or the float is sticking or broken. This will make the engine run rough. You will need to clean or replace.

Replacing any old fuel lines and the primer bulb can help as the valves in them can swell over time and restrict fuel flow.

Retuning as Frank?s sticky is a good idea. Idle speed is important to prevent the engine stalling when shifting into gear. I would check compression and spark first. No point tuning until you are sure these two things are OK.

Broken or bent reed valve can cause difficulty in idling. This is not my area but as I have heard the 1996 and later motors had problems in this area. If after you have tried the above you still have a problem it may be something to look at.

The answer to you previous question regarding the breather for my full tank. I had a problem with the breather hose to my in-floor fuel tank. The breather hose was meant to run along the top of the fuel tank which let any fuel that went to the overflow spout whilst filling drain back to the tank under gravity. The hose dropped down the side of the fuel tank making a u- shape in the hose that collected fuel. The breather hose is about 10 feet long so it would hold a fair amount of fuel. At idle the fuel pump was not strong enough to suck air back into the tank past the fuel. I became aware of the problem when I would get fuel blowing back up the filler hose when filling.

You will get it sorted. It is just a mater of tracking down the problem. You have eliminated a few already.

Good Luck

 

[kywings]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

TwoFish, I have never messed with a float before. Can this be done on the motor? I read my manual and it has instructions as part of a rebuild scenario. It would seem I can do it attached. I borrowed a tester and will check compression today or tomorrow. Last night I removed the quick disconnect on the main fuel line and ran line direct to pump. It felt a little smoother so I'm going to order all new line. Any thoughts on removing the quick disconnect all together? Seems like something else to fail. Still wanted to stall at idle. Ill keep you informed. Thank you for the advice.

 

[TwoFish]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

I have one quick connector by the fuel tank so I can change from the in floor tank to a portable tank. It?s probably good to have one in the line somewhere so you can disconnect in a emergency.

You could clean the needle and seat by removing the bowl on the bottom of the carby. Use a cotton bud spayed with carby cleaner to clean the seat. Check the top of the needle for wear as the drawing attached.

You can test the float by seeing if it will float in petrol. Submerge it to see if it bubbles or shake it to hear if there is any petrol sloshing around inside it.

The only way I know of to set the float level is to remove the carby and hold it upside down with the float, needle and seat in place. The line on the side of the float should be parallel with the edge of the carby nearest the float. (the bottom edge of the carby which is the top edge now as it is upside down).

If you decide to take the carby off it wouldn?t hurt to put a carby gasket kit through it and give it a clean at the same time. I don?t think the kits are very expensive. I have heard that it is best not to soak the carby in a cleaner as some of the rubber seals can swell. Use a spray cleaner. I would not try to remove the main jet but you could remove the idle adjustment screw and spray cleaner in there. Give it a blast with compressed air if you have it.

Another thing to check is the fuel enrichment solenoid. It sits under the carb and is attached by hoses to the base of the bowl at one end and to the throat of the carby at the other end. This feeds fuel directly from the bowl of the carby to the engine when you push the key to choke the engine. If it doesn?t open the engine will be hard to start when cold. If it leaks the engine will run rough and be impossible to tune. Test it by removing the hoses and pushing the black button on top of the solenoid. With the button pushed air should pass through. Air should not pass through otherwise. Push the key in to make the choke work. You should hear the solenoid click open and closed.

I had trouble with the choke solenoid rubbing on the intake manifold. The rubber grummet that holds the solenoid had worn over time and the wires were rubbing away. It will not effect the idling but worth checking while you are looking.

Hope the compression test is OK.

Good Luck

 

[kywings]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

If it does not rain I will check compression tonight. Hope it is ok too. Since this motor has lacked TLC for years I think it is important to make it right so I'm going to order the Carb rebuild kit. I saw in another thread someone who was also fighting this battle and pulled his pick up tube from his tank and found the screen almost completely plugged. Will pull this weekend just for kicks. A little more clear on the choke and will perform those checks as well. I Really appreciate the detail!. Thanks

 

[TwoFish]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

The carb gasket kit I'm thinking of only has about 4 or 5 gaskets so should be fairly cheap.

 

[kywings]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

As of now I have prices from 16-31 dollars. There are two Kits a 18-7033 which has the least amount of parts and 18-7037 which has the most. Napa claims the 75 hp has two different makers of cabs. Making calls now.

 

[kywings]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

Do you know whether the carb is a TC or a WB. I cant fin a way to distinguish between the two.

 

[kywings]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

Do you know if the Carb is a TC or a WB. I cant find a way to distinguish between the two.

 

[TwoFish]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

No I can?t help you there. I ordered my carb kit locally and they went by the year and serial number.

This ne fits my motor http://www.crowleymarine.com/parts/3817.cfm

 

[kywings]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

Thanks. They don't show the needle and seat in the kit but their site has the 18-7033 kit that has it all. It just does not list the engine. I'll call them in the morning.

 

[kywings]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

Well heres where I'm at. Fuel enrichment works fine. Opens when pushed and closes when released. Clicks when choke is pushed. Received the kit and needle and installed tonight. While I had it in the bench I cleaned it up. I followed the Clymer manual instructions. It had a step to clean the main jet and it seemed green and crusty so I removed it and cleaned it. It also had a step to remove the main nozzle. I was able to turn but after 3+ turns it never unscrewed. It just turned. So I left it alone and returned it to its original position which it seemed was angled facing the engine. I'm nervous about this not sure why it would not unscrew. Hope I did not mess it up. Could not remove the intermediate jet as the manual said it had a screw plug but it was the shot kind. Sprayed cleaner through it. Float seemed fine it was the plastic kind and had no fuel in it. The needle was SHOT. Worse than the picture you sent.

Results:
Positive's-Primer pumps up hard now. Did not see any gas leaking. Engine still starts hard but runs a little smoother. It appears to have a little more responsiveness to the throttle. When you put in neutral the rpms slow as you adjust the throttle instead of slowing at its own pace after the throttle is moved. When you shut the engine off it restarts without needing to be primed.

Negatives- Still has a hard miss. Now that it runs smoother it seems I can feel a slight miss at WOT. Never felt it before but always ran rough. I ran it down the lake and back and stopped several times and it idled fine without stalling. Got back in front of my dock and for fun I tried a hole shot to see if it hesitates. I was curious if I had the mixture screw correct. It hesitated then stalled. Very hard to start and then now every time I put it in gear it stalls. It will idle and I can increase RPMs in neutral but in gear it stalls. Luckily I was by the dock. I still need to check compression. Is it ok to turn over with plug removed. I read some posts that it could be bad. Not sure. Also is there a way to check for spark without a tester? I'll buy one if needed. On my motorcycle I have held plug by a ground. Three things I have noticed while working on this. One, metal shavings all over. Not sure of previous owner had major starter issues. I could not find much ground up. Just evidence of scrap marks under the flywheel like maybe at some point in its life something broke. Second, the little black box that the top spark plug wire goes into looks like it cracked at some point in its life and someone calked it. Third, a few weeks ago the nut fell off of the starter and when I fished it out of the bed it had a magnet attached to it. In another post someone told me there are magnets under the flywheel. Not sure if its old or not.

Sorry for long post.

 

[pnwboat]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

Look up under the flywheel for a missing stator magnet. Missing magnet will not allow the stator to generate the proper ignition/charging voltage.

This is what the flywheel looks like from underneath.

 

[roscoe]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

Try turning the fuel mixture screw 1/4 turn counter clockwise.

 

[kywings]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

pnwboat, thanks for the pic. The magnet I found is much smaller, possibly a brush from the starter or if possible a broken end of the stator magnet. I'll try to look tonight. I feel better knowing what these look like.

I will adjust the mixture screw tonight and see if it helps.

 

[kywings]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

For anyone having issues with fuel pressure or primer bulb not holding pressure, I attached a pic (not great) showing good and bad. Bad being the red tip on right. Replacing the float needle fixed this immediately.

 

[kywings]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

On the front of the carb it looks as though there is torn metal on the top nut. Does anyone know if there is something missing? Did not see anything in the manual.

 

[TwoFish]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

Good to see you are getting a few things sorted.

The CDM modules can be damaged if you don?t ground them. To run a compression test just flip the safety lanyard switch on the forward control so no power goes to the ignition. You should still be able to crank the motor but not damage the ignition. I do this when servicing the engine to check that the safety switch is working. I start the engine and then flip the switch to check that it stops the engine. Failing this you ground the spark plug wires to the block of the engine. I usually disconnect the fuel line for this test as well.

You can test the sparkplugs by grounding them whilst out of the motor to check them. Just make sure they are all grounded. Another forum member made up a wooden device that that help all the plugs with the sparkplug wires attached. He then had a ground wire which clipped to the block of the engine that earthed the sides of the plugs. You could test all the plugs at the same time.

The calked CDM module may be the source of the miss at high revs but do your compression check before you worry about it.

Replace you old fuel filter if you haven?t already. I read the problem you had with a new on but try to find on that works. It just eliminates another potential problem.

Don?t know where the metal filing are from. I have seen posts where screws under the flywheel come loose and cause metal to be shaved off. Hopefully someone can comment on this.

I?ll check the front of my carb tomorrow for any metal fitting.

Good luck.

 

[kywings]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

This morning I did two things. I turned the main tube in the carb so the angle is turned to the right. As I stated I wanted to clean it per the Clymer manual. I started to unscrew but it only turned and did not come out. I had taken a picture before I disassembled the carb and saw I angled it the wrong way when I reassembled it. I also backed out the mixture screw 1/4 turn. I spent an hour going up and down the lake turning it in and out. Currently the mixture screw is 1 1/4 from lightly seated. It starts the same and I picked up another 150 rpms. Now the problem is at any RPM it has a burble. If I back the mixture screw out it gets worse and if go in it will stall. In between burbles it runs smooth. I might even say smoother than before I rebuilt the fuel pump and carb.

My boat has no safety switch so Im not clear on how to perform a compression test. Im going read a little in the manual. Also bought a spark tester. I looks like a pen and it sets on the wire and lights up. Works on my car but does not light up on boat. so I will need to make the wooden block idea.

Another thing i noticed is when I removed the bowl to adjust the main tube there were several small white flakes at the bottom. I had just cleaned this thing real well so I'm thinking the I really need to get the fuel filter changed. I'm going to install the Napa one again now that the carb is rebuilt. Probably end up ordering a Merc one if this one fails again. :facepalm:

 

[kywings]

Re: 1998 75 HP Force. Misses, stalls hard to start.

Re: 1998 75 HP Force. Misses, stalls hard to start.

Ok.. so was frustrated all day, so this afternoon I removed the carb...again. The Clymer manual stated that the idle tube needed to be in contact with the main tube so I thought Id check it. It seemed like it was but I turned the main tube a little and made sure it was. While the carb was on the bench I removed the mixture screw again and loaded it with carb cleaner and compressed air to insure all the ports were open. Fuel in bowl appeared clean.

TwoFish advised earlier to inspect the fuel enrichment valve and check the wires. I did that but briefly as I was out of daylight. The two black wires looked ok and blowing thru the valve showed the valve was working. TODAY in the sun I noticed that one of the black wires was actually a yellow wire with dirt. So I removed the valve to clean the wires and found both wires worn away and shorting directly to the motor. Now.. once this afternoon and once this evening the motor started on the second try when cold.

A few weeks ago in frustration I bumped the idle so it would not stall when docking. Tonight after the second carb cleaning and fixing the short, idle at the dock with no load is now 1800 when it was 1100 this morning so maybe I'm making progress. Plan to adjust the idle back down and readjust the mixture. Seems to run better but still burbles.