90 HP Force bogs when throttling up

[aisler]

Hi all.

Have a long standing issue with my 1998 90 HP Force (Serial 0E325251). It has been bogging down and dying when you give it gas. If you hit the key when it is bogging, it will take off. It idles great and runs great on the muffs. Here is a long list of everything I have done or had done:


new powerhead - cracked a cylinder, assumed that that was causing this issue but it was not.
all new engine gaskets
new fuel pump
new fuel lines from tank all the way through to the top carb
full carb rebuild (twice, no new floats just needles)
new primer bulb
new fuel filter
checked vent screen on gas cap
cleaned screen on fuel pick up in tank
timing adjusted
new recirc hoses
3 new recirc valves (only the T shaped ones, 2 were allowing air back in)
raised motor (one mechanic thought it was loading up)

At a complete loss here. Got some great tips from a fellow on another board, he suggested I post here too.

 

[bentle]

Re: 90 HP Force bogs when throttling up

First do a compression & spark test. Good compression is important for the fuel pump to function properly. If all is well there then it does sound like your fuel pump may be your problem. Check diaphragm and make sure gasket is in the right place as well as the diaphragm. Its real easy to put the to in the wrong place. Does the primmer bulb hold the fuel after prime or does it go flat while motor is running. This would indicate a bad fuel pump diaphragm. If your floats in the carbs are not adjusted properly then adjust as needed. You may need to remove them and make shure they are not full of fuel. If you don't have a manual for your motor then get one asap. This will help you to do alot of your repairs.

 

[aisler]

Re: 90 HP Force bogs when throttling up

Compression is perfect, actually was before the new powerhead as well, until it got real hot then the crack would let water in.

Fuel pump is new, bought the Quicksilver one and it came all put together. Assume the carbs are adjusted properly as it was done 2 times by different folks and the floats were submerged overnight and did not fill up.

Primer bulb is new and it holds pressure no problem.

 

[droach77]

Re: 90 HP Force bogs when throttling up

When you say you are hitting the the key does that mean you are activating the fuel enrichment solenoid. If so than it sounds like your carbs are still messed up. You should really get the welch plugs out to do a full service carb cleaning, they are cheap and easy to get. Does it lean backfire alot also?? I had severe carb deterioration and had to get new carbs, i was amazed at the difference, but before you do that, replace the float needles and Idle mixture screws pop the welch plugs out and give the carbs a real thorough soaking and cleaning then link and sync. Also make your idle mixture screws are properly set, start at 1 1/14 turns and go from there. GOOD LUCK


dave

 

[bentle]

Re: 90 HP Force bogs when throttling up

Do you have a manual? If not then get one as soon as possible. We can give you advice and some steps to help get you started hopefully in the right direction. Now using this advice with a manual for your motor is a huge plus and can help to fill in the blanks. Have you been able to verify that you are getting good spark at idle and wot. Some inline spark testers work well here. If one cylinder is not getting fire then it to will cause this problem. If timing is off even one degree then same problem. Carbs need to be getting enough fuel in the bowls at wot to maintain rpms as well ad to each cylinder. Were the reeds also replaced with the new powerhead if not then its another place to look. Hope this helps and there are others that will chime in with good advice.

 

[aisler]

Re: 90 HP Force bogs when throttling up

When you say you are hitting the the key does that mean you are activating the fuel enrichment solenoid. If so than it sounds like your carbs are still messed up. You should really get the welch plugs out to do a full service carb cleaning, they are cheap and easy to get. Does it lean backfire alot also?? I had severe carb deterioration and had to get new carbs, i was amazed at the difference, but before you do that, replace the float needles and Idle mixture screws pop the welch plugs out and give the carbs a real thorough soaking and cleaning then link and sync. Also make your idle mixture screws are properly set, start at 1 1/14 turns and go from there. GOOD LUCK


dave

Yeah, its the fuel enrichment solenoid. I assumed they did a full service cleaning, but maybe I am wrong

Will try it

 

[aisler]

Re: 90 HP Force bogs when throttling up

Do you have a manual? If not then get one as soon as possible. We can give you advice and some steps to help get you started hopefully in the right direction. Now using this advice with a manual for your motor is a huge plus and can help to fill in the blanks. Have you been able to verify that you are getting good spark at idle and wot. Some inline spark testers work well here. If one cylinder is not getting fire then it to will cause this problem. If timing is off even one degree then same problem. Carbs need to be getting enough fuel in the bowls at wot to maintain rpms as well ad to each cylinder. Were the reeds also replaced with the new powerhead if not then its another place to look. Hope this helps and there are others that will chime in with good advice.

I have the SELOC manual. Have read it cover to cover at this point. Have tested fire on all plugs and they are all working. Timing was adjusrted by the mechanic with me in the boat on the water, so I know it is right. Not sure on the reeds though. I assume they checked them but did not replace them.

 

[bentle]

Re: 90 HP Force bogs when throttling up

Well it sounds like you need to pull carbs and clean. After carbs are off then you will be able to look ip in the intake and check reeds. If your careful when removing carbs then you may not have to replace carb gaskets. Reeds should be strait and seat flush with mounting plate. Basically you shouldn't be able to see past the reed peddles. Now your carbs may need a simple link and sink and can be found at the start of the forum page.

 

[aisler]

Re: 90 HP Force bogs when throttling up

Okay, I am going to pull the carbs and reed plates.

Any one have any idea what the part number is for the reeds for this motor? Is it a 4 petal reed?

 

[aisler]

Re: 90 HP Force bogs when throttling up

Back to this old topic. I finally got around to doing a full rebuild and Linc/sync. Pulled welch plugs new everything in the carbs. Ran great in the driveway. took it to the lake yesterday and same issue. Seems really bad when trying to put it on the trailer.

So I am basically still at square one. All new power head and all the other stuff and still crappy performance.

Any other ideas would be appreciated.

 

[Justinde]

Re: 90 HP Force bogs when throttling up

Wait till Frank or Jerry chip in here mate- they are the Yoda's of Force Engines

My 2 cents- I would be winching my boat on the trailer. If its a big boat- get an electric winch. The possible epic fails that can happen 'driving' your boat onto the trailer are far outweighed by a possible sore arm from winching.

Just my 2 cents. About your initial issue, I'll go back to basics.

You have fuel. You have Spark. You have compression. You have everything you need for an engine to run. If you did the Link & Sync correctly, its probably a timing issue. I understand that your mechanic and you did the timing, re-check it.

If the timing is correct, it could be a loose/weak/missing magnet under the flywheel. I don't think it would run well, if at all with a missing magnet- Frank/Jerry chip in here.

Points to a timing issue for me.

Cheers

 

[bentle]

Re: 90 HP Force bogs when throttling up

Usually when a motor bogs and dies its fuel related.
If the primmer bulb is going flat then something is restricting fuel from the tank
the primmer bulb such as plugged pre screen or filter or plugged fuel vent.
Check quick connects for plugging.
If all is good there then fuel restriction is from fuel pump to the carbs.
Like fuel filter, bad fuel pump diaphragm incorrect float adjustment, carbs out of sink, air entering fuel lines, any kinked fuel lines?
Does your overheat warning buzzer work?

Sometimes they can get disconnected and if the motor runs to hot then it will bog and die.
Another is to perform a compression test on all cylinders just to make sure.

if the compression is to low then fuel pump cannot deliver enough fuel to keep it running at
wot. If your able to bump the fuel enrichment on the key and get it running again then its almost for certain fuel related, or comp.

 

[Justinde]

Re: 90 HP Force bogs when throttling up

If he has replaced everything as per original post, I would have thought timing- but as you said, it would be starving if you can hit the key and have it run OK. K.I.S.S- Keep it simple stupid. I'd start with the easiest thing to check- tank and primer, and work back into the engine. Has anyone squeezed the primer instead of hit the key to see if that has the same effect??

Wasn't calling you stupid- its an old acronym.

 

[aisler]

Re: 90 HP Force bogs when throttling up

I think the same thing, fuel somewhere, but everything is new. Compression is 120 on all cylinders. Buzzer works now. That was part of the reason I ended up getting a new head. Thermostat wire was messed up and never told me it was overheating.

I replaced it and verified the buzzer.

Usually when a motor bogs and dies its fuel related.
If the primmer bulb is going flat then something is restricting fuel from the tank
the primmer bulb such as plugged pre screen or filter or plugged fuel vent.
Check quick connects for plugging.
If all is good there then fuel restriction is from fuel pump to the carbs.
Like fuel filter, bad fuel pump diaphragm incorrect float adjustment, carbs out of sink, air entering fuel lines, any kinked fuel lines?
Does your overheat warning buzzer work?

Sometimes they can get disconnected and if the motor runs to hot then it will bog and die.
Another is to perform a compression test on all cylinders just to make sure.

if the compression is to low then fuel pump cannot deliver enough fuel to keep it running at
wot. If your able to bump the fuel enrichment on the key and get it running again then its almost for certain fuel related, or comp.

 

[aisler]

Re: 90 HP Force bogs when throttling up

I certainly feel stupid:facepalm:I am an engineer by trade, I should be able to get this figured out....

What about reeds or the magneto/stater?

 

[jerryjerry05]

Re: 90 HP Force bogs when throttling up

Try disconnecting the fuel enricher or choke.
A new fuel pump diaphram can go bad in 2 seconds.
One cough/backfire can put a hole in it.
I worked on a 97 120 had the carb apart 4 times before it was right.
A tiny piece of dirt was the problem.
I install a filter from Wally World.G-2 or G12 depending on hose size.

 

[bentle]

Re: 90 HP Force bogs when throttling up

Bad reeds would give you alot of spitting coughing or backfire out of both exhaust and carbs, plus a lot of fuel out of carb openings while running the motor. A bad stater would give you week spark on one or all cylinders and weak charge to your battery.
If the motor is bogging down and dying its most likely fuel related.
Is there an in line fuel filter? Make sure its flowing fuel in the right direction.
If all is well from tank to pump then recheck from pump to the carbs.

 

[aisler]

Re: 90 HP Force bogs when throttling up

There is a new fuel filter and it seems to me right.


It for sure seems like a fuel issue.

What about the vent. Is there a way for it to cause any issues? How could I test it?

 

[pnwboat]

Re: 90 HP Force bogs when throttling up

You can eliminate the vent by taking the gas cap off, or just loosening it to where it will allow air into the tank.

 

[aisler]

Re: 90 HP Force bogs when throttling up

So I thought i would try the vent without running it as I am not able to get to the lake today. it is one of those Perko gas fill caps. The picture below is what I did. Does it make sense where the air is coming out?

with the gasket in, the air comes out the vet hole on the tank (where the hose is supposed to be), presumably it is coming out the outlet under the cap and recirculating back through the fill hose. Without the gasket, the air releases from the cap area.



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