force 85 issue

[i989240sx]

Re: force 85 issue

oh and another thing i rules out any fuel problem as far as the right mixture bc i took a seperate gas can out with me and mixed a perfect 2 gal mixture. and that tank had the same result.

 

[john from md]

Re: force 85 issue

Try this test. Run the engine until it stalls out. Feel the primer ball, is it soft? Next, pump the ball and try to start engine, does it start? Next, have someone pump the ball as you are driving, does the engine still run?

If you answered yes to these three questions, there is a excellent chance that the three check valves in your fuel pump housing are sticking. They cost $5 apiece and two are easy to change the third needs a special puller or cutting out with a dremel.

Regards,

John

 

[pnwboat]

Re: force 85 issue

If the primer ball and fuel pump check valves are OK, I would say you've covered all the bases in regards to the fuel delivery (carbs, fuel pump etc). Time to look at the ignition system and air delivery.

Ignition system - Make sure all your grounds are clean and making good contact. Each coil has a ground wire that goes to the mounting plate under the bolt that holds the coil in place. There is also a ground wire that runs from the mounting plate to the block. There is a 10 or 12 position terminal strip on the mounting plate. The spade lug connectors on the wires attached to the terminal strip have a small piece of black heat-shrink on them. Sometime the wires will break inside the heat-shrink causing no or intermittent ignition function. Look at the spark. You should have a strong snappy blue spark from the coils. If you are having trouble determining the spark visually, try this. With the engine warmed up and idling in your test tank, pull a spark plug wire off one at a time. There should be a noticeable decrease in idle speed. If you pull a wire off, and the idle does not change significantly, then I would suspect you have weak spark on that cylinder. NOTE: When you pull the wire off, be sure to ground it to the block. There is a possibility that you may damage the CD Module if you don't ground out the spark plug wire with the engine running.

Reed valves - Easy to check. The reed valve plate assy. is located under each carb. Take carbs and carb adapter off and pull reed plate assy out and visually check the reed valve petals. They should be intact, no pieces broken out or cracks. Reed valve petals should be laying flat and not lifted or bent up. NOTE: There is a gasket on the plate assy. Be careful not to damage when pulling assy. out.

Try those steps and see what you come up with.

 

[i989240sx]

Re: force 85 issue

ok the primer ball is alittle soft its not rock hard but not really soft eather everytime it stalls it pritty much starts right back up pumping the ball again or not. umm if the engine is running at an idle or at wot and i pump the ball the engine will shut down like it was flooding it out right away. what do you think

 

[pnwboat]

Re: force 85 issue

Sounds like you have a needle valve in the carb that is stuck open either from debris or the float level is set too high. Pumping the primer bulb while under way should have little or no effect on the way the motor runs if everything is set correctly. Adding an inexpensive inline filter between the pump and carbs is also cheap insurance to prevent crud from getting into the carbs. The filter screen on the inlet cap of the fuel pump doesn't do a very good job.

What kind of floats do you have in the carbs? Are they the solid black foam plastic type or the white hollow plastic ones (White color may have turned brown with age)? Reason I ask is I have a 1988 125HP that had the solid black foam type floats. I set the float according to specs. Carbs kept leaking gas and primer bulb would not get very hard. I had to set them a tad lower than factory specs. to keep the carbs from leaking when I pumped the primer bulb. I later replaced them with the white hollow plastic floats from later model engines and set to factory specs with no problems. I suspect that after 20+ years of soaking in gas, the original floats where not quite a buoyant as they once use to be.

 

[i989240sx]

Re: force 85 issue

the floats i have are brass. and how do you change the level of them.

 

[pnwboat]

Re: force 85 issue

Brass is good. The little tang on the float that rides against the needle valve is bent up or down to adjust the float level. Seems kind of primitive but it works. Be careful not to put any pressure on the needle valve itself or you may damage the small end of the needle valve that seals.

The manual has a better explanation. To set the float levels you have to take the carbs off and remove the fuel bowl. Turn the carb upside down. The float will kind of flop around. Hold the carb so the body is level upside down. The top of the float should be almost perfectly parallel to the body casting of the carb where the bowls seal. There is an actual measurement in the manual. The measurement is the distance between the top of the float at the very end and the body of the carb.

Not sure how clear that is, but the manual w/pictures is much better.

Here is a crude drawing. Remember, carb is upside down. Top illustration, float is set correctly. Middle illustration, float is set too high. Needle valve may allow too much gas resulting in flooding. Bottom illustration, float is set too low. Needle valve may not allow enough gas resulting in lean condition. Excessively lean condition can damage pistons.

 

[i989240sx]

Re: force 85 issue

ok thanks i will do that and im gonna take off the manifold and check the reeds see what they look like i will let you know.

 

[i989240sx]

Re: force 85 issue

hey guys i took the carbs and the reed plates out and i can hear something inside one of the cylinders at least i think it is in there ratling like a loose part or a peice to a bearing when i turn the flywheel i thought it could of been a broken ring but i took the head of and all of that is fine and there doesnt seem to be any play in the crankshaft brgs. what do you think is there anything in there or maby the tranny that could be making the noise that is normal
.

 

[pnwboat]

Re: force 85 issue

I doubt anything in the lower unit would cause noise like that in the power head if it's in neutral.

You really can't determine conditions of the rings are doing by looking at the top of the pistons unless there has been a catastrophic failure with obvious piston damage. See this post w/pictures for what pistons look like from the top when a ring breaks.

http://forums.iboats.com/showthread.php?t=266436&highlight=piston+damage

Easiest thing to do is a compression test. Sometimes that doesn't tell you the whole story. As in the example above, even w/a broken ring, two of the cylinders had fairly decent compression.

Kind of difficult to make a determination without actually hearing the noise.

 

[i989240sx]

Re: force 85 issue

yea all of my pistons are clean no scores they look perfect including the cylinder wall and intake and exaust ports all look great. im going to go on the conclusion that it is a bearing causing this noise and im gonna run it until it dies plan on buying a new boat this winter anyways. thanks for your help

 

[Matthew A.]

Re: force 85 issue

If your engine has the prestolite ignition system, two blue or black cdi modules located on the starboard side of the motor, it maybe a classic case of intermittent spark. Either from an ignition coil not generating spark all the time either due to a bad coil, coil wire, connection or, a cdi module going bad or about to go bad and not sending voltage to one of the coils.

You mention that it seems the hotter the engine the more the issue arises. Classic coil or module senario.
Loose fuel line connections at the carbs and fuel pump can also come to bear when the engine warms and softens the rubber hose abit.

Also, did you happen to notice what size jets are installed in the carbs. Make sure the jets in your carbs are correct for the altitude in which you use the motor.

 

[i989240sx]

Re: force 85 issue

thanks matthew i was thinking spark but i would test it and it would be fine but if its doing it intermediatly i wouldnt know that. what do you think i should do about this problem. is there a test i could do.

 

[NYForce]

Re: force 85 issue

When my cdi went in my 85hpforce,i was going 5000rpm,stopped for a minute,then it maybe went half of that at full throttle.Local marina knew what the problem was right away.

 

[i989240sx]

Re: force 85 issue

i live in the ny poughkeepsie area and i dont know where to take it. i would like for a mechanic to look at it deffinitly take a ride with me or something. you know.

 

[i989240sx]

Re: force 85 issue

if i was to try and start replacing ignition pieces should i start with the coils or the switch boxs the switch boxes on this site are 230 each. what was it exactly on yours.

 

[i989240sx]

Re: force 85 issue

ok so after i took everything apart checked the reeds checked the pistons cleaned the carbs again put in line fuel filters before and after the fuel pump i took it on the lake and still the same result nothing changed. so im forced into believeing its a spark problem i need someone to tell me the way to test each and every coil and module so im not just spending away my money on things i dont need i think you test that stuff by resistance. help anyone thanks. ...

 

[chitownborn]

Re: force 85 issue

this is the way i found my intermintant coil, take the boat to the water, bring a timing light and tape the trigger on the timing light so its on all the time during the test. now take your cowling off and hook light up to the spark plug wire, lay the timing light on the seat now go to wot and keep an eye on the light if it continues to flash showing no signs of failure go to the next cylinder etc etc. mine drove me nuts and i couldnt find it untill i did it this way, my no 2 coil was going open at wot but would work just fine at low rpm s hope this helps don

 

[i989240sx]

Re: force 85 issue

yea i wil deffinlitly try that. does anyone have part numbers for the coils and the controlers. on this site are they caled switch boxes. i dont want to buy if im not sure thats the right part.

 

[i989240sx]

Re: force 85 issue

hey everyone i have an update finnally i replaced all 3 coils and the boat never ran smoother but now there is a little hesitation when i throttle it up. there is alittle play in the timing advance control lever. if thats what its called could this be the problem. and also has anyone ever herd of if the throttle cable became loose it wouldnt return the carbs back to idle it was reved just alittle bit and it would keep stalling when i tryed to move but if i returned it back to idle it would run fine.. could this be a timming issue also like the control lever is at idle and the carbs are not... well im convinced that i have solved the problem ive had for a long time and i just need to do some adjustments. well im looking forward to hearing what everyone thinks..n thanks guys