Force 85 (1985) Doesn't like to do more than idle in water - and often dies on its own

[cooperglee]

So I bought this boat about 2 months ago and have never been able to get the motor to "run" in the water... Will run on muffs in driveway and will idle when I get it in the water but can't get it go above 1000 rpm in the water (I have done the stupid thing and put it in gear in the driveway to check and it will go to 2500). When I try to give it throttle in the water it just bogs and dies... I have replaced the plugs and checked the compression - 145 on all 3 cylinders... Have tried separate small gas tank with fresh 91 Octane and 50:! mix and have sprayed a lot of carb cleaner directly into each - lots of white smoke but it seemed to choke through it. It also often just dies on its own in the driveway (with motor in a tall trashcan with water above exhaust) or at idle in the water... I am at a bit of a loss now - the only other thing that I think might be suspect is the fuel pump/diaphragm... I adjusted the idle up a bit to see if that would help and doesn't seem to make much of a difference... Anyone have any magic insight? Thanks in advance

 

[Nordin]

As you have checked comprerssion in all 3 cylinders and it is 145 PSI the next step is to check for spark at all 3 cylinders.
If spark is okey then clean the carbs, check the float levels and then set the air/fuel mixture screws at 1 1/4 of a turn out from lightly seated.
Then you have to set the throttle pick up point and the timing.
There is a sticker in top of this forum by FrankA how to set the throttle pick up and the timing.

 

[jerryjerry05]

Always include the year, model and serial# if possible.
Fuel pump. ??
The factory sent out a service bulletin in the late 80's that the air screw should be set at 1 turn out and left there. BUT!! not all motors run at that setting. I found 1 1/8th turn worked great on my motors.
One of my customers needed his set at 3 turns out???
Check the fuel pump diaphragm.
Do a starting fluid test, spray SF around the intake side, around the bases of the carbs and under the packs, if that makes it run different?? Then it's sucking air.

 

[cooperglee]

As you have checked comprerssion in all 3 cylinders and it is 145 PSI the next step is to check for spark at all 3 cylinders.
If spark is okey then clean the carbs, check the float levels and then set the air/fuel mixture screws at 1 1/4 of a turn out from lightly seated.
Then you have to set the throttle pick up point and the timing.
There is a sticker in top of this forum by FrankA how to set the throttle pick up and the timing.

Have checked all three and they seem good - have also lightly seated all 3 screws and then backed them out 1 1/4 - 1 1/2 turns... I'll look for the FrankA post about pick up and timing - maybe that is what I am missing

Thank you!

 

[cooperglee]

Always include the year, model and serial# if possible.
Fuel pump. ??
The factory sent out a service bulletin in the late 80's that the air screw should be set at 1 turn out and left there. BUT!! not all motors run at that setting. I found 1 1/8th turn worked great on my motors.
One of my customers needed his set at 3 turns out???
Check the fuel pump diaphragm.
Do a starting fluid test, spray SF around the intake side, around the bases of the carbs and under the packs, if that makes it run different?? Then it's sucking air.

year is 1985 - serial is 4060

I'll spin the screws a bit more - I had done as the factory manual indicates which is to twist them to both extremities - i.e. too rich and too lean and then determine what the "mid" point was by dividing the number of turns between the two points in half - that just so happened to be about 1 1/2 turns out from lightly seated.

How should the fuel pump diaphragm look other than not torn or warped? For under $30 it looks like I can get a replacement on Amazon - seems like it might be worth the $30 to just change it once I take it apart..

Thanks

 

[The Force power]

Have checked all three and they seem good - have also lightly seated all 3 screws and then backed them out 1 1/4 - 1 1/2 turns... I'll look for the FrankA post about pick up and timing - maybe that is what I am missing

Thank you!

Here's the old post (from the late Frank) that I have printed out & live by;
1.Disconnect the ball link to the carb cam at the timing tower. Disconnecting at the cam risks bending the cam. Move the cam away from the carb roller.
2. Loosen the screw(s) on the aluminum tie bar and let all carbs close completely, then tighten again.
3. Set the cam so that the scribed line is pointing directly at the black roller on the carb lever. If the cam has two closely spaced lines, set the black roller directly between them.
4. The black roller is held with an offset screw and nut. Loosen the nut and turn the screw until the black roller JUST touches the cam. Tighten the nut and re-attach the ball link maintaining the scribed line at the roller.
5. Adjust the ball link so that at full throttle the bottom carb butterfly opens substantially horizontally. Adjust the aluminum tie bar so all carb butterflies open equally at full throttle. They need not be perfect but should be rather close to horizontal for best performance.
6. Adjust timing to 28 degrees before top dead center at full throttle. ( STATIC TIMING / CRANKING SPEED )
7. Adjust idle speed to 700-750 RPM in the water in forward gear. Do this with the screw on the bottom of the timing tower. Loosen the locknut and adjust. Screwing in increases idle speed. Do this in small increments and let the engine rev and adjust itself before the next adjustment. A little goes a long way here. When correct, tighten the nut. Note that the scribed line on the roller will now be (usually) below the black roller a bit.
8. NOW we adjust the mixture on the carbs. Set all low speed needles to about 1 1/4 turns out from lightly seated. Do not force as this will damage either the needles or the seats.
8A. With the engine idling in neutral, turn each the needles in equally about 1/8 turn at a time. Give the engine a couple of seconds between each adjustment to stabilize. Adjust until the engine either "sags" or stalls. Note this setting.
8B. Now go the opposite direction. Adjust until the engine runs rough, burbles, or stalls. Note this setting.
8C. Set all needles to the average between the two settings: That is, for example, if it stalled at 3/4 turn out and burbled at 1 1/4 out then set all needles to 1 turn out.
8D. Readjust idle speed to 700-750 RPM.
9. Take the boat out on the water and do a "hole shot"--Full throttle acceleration from a stop. If the engine "sags" then recovers and picks-up it is too lean. Open the needles about 1/16 turn at a time until the engine accelerates with no hesitation.
If the engine sputters or coughs or burbles, then clears itself and accelerates, it is too rich. Close the needles about 1/16 turn at a time until the engine accelerates smoothly.

10. I can NOT stress this enough! NEVER set the low speed needles less that 1 turns out no matter how poor the idle or acceleration. To do so will run the engine too lean and detonation and melted pistons at or near full throttle operation will result.

 

[Jiggz]

Invest in a $6 in-line clear fuel filter and connect it between the fuel outlet and the carbs inlet hose. This will help you diagnose fuel related problems big time.
Double check the "Link and Synch" post on the top to make sure it's timed correctly with the carb opening.
A simple test to find out if there is exhaust link. With cowling cover off, check for smoke coming out of the exhaust, the LU connection to the Upper unit and then the exhaust relief hose which is the corrugated hose that outputs to the mid-leg. Any exhaust leak will kill a motor as soon as it goes into the water with the cowling cover on. If you remove the cowling it will continue to run.

 

[cooperglee]

Invest in a $6 in-line clear fuel filter and connect it between the fuel outlet and the carbs inlet hose. This will help you diagnose fuel related problems big time.
Double check the "Link and Synch" post on the top to make sure it's timed correctly with the carb opening.
A simple test to find out if there is exhaust link. With cowling cover off, check for smoke coming out of the exhaust, the LU connection to the Upper unit and then the exhaust relief hose which is the corrugated hose that outputs to the mid-leg. Any exhaust leak will kill a motor as soon as it goes into the water with the cowling cover on. If you remove the cowling it will continue to run.

Thanks for the insight! I am planning to get to a lake tomorrow to do further testing/troubleshooting - the exhaust leak is one I had not even contemplated - if that turns out to be it I will be forever grateful - never would have thought about it!

 

[cooperglee]

Here's the old post (from the late Frank) that I have printed out & live by;
1.Disconnect the ball link to the carb cam at the timing tower. Disconnecting at the cam risks bending the cam. Move the cam away from the carb roller.
2. Loosen the screw(s) on the aluminum tie bar and let all carbs close completely, then tighten again.
3. Set the cam so that the scribed line is pointing directly at the black roller on the carb lever. If the cam has two closely spaced lines, set the black roller directly between them.
4. The black roller is held with an offset screw and nut. Loosen the nut and turn the screw until the black roller JUST touches the cam. Tighten the nut and re-attach the ball link maintaining the scribed line at the roller.
5. Adjust the ball link so that at full throttle the bottom carb butterfly opens substantially horizontally. Adjust the aluminum tie bar so all carb butterflies open equally at full throttle. They need not be perfect but should be rather close to horizontal for best performance.
6. Adjust timing to 28 degrees before top dead center at full throttle. ( STATIC TIMING / CRANKING SPEED )
7. Adjust idle speed to 700-750 RPM in the water in forward gear. Do this with the screw on the bottom of the timing tower. Loosen the locknut and adjust. Screwing in increases idle speed. Do this in small increments and let the engine rev and adjust itself before the next adjustment. A little goes a long way here. When correct, tighten the nut. Note that the scribed line on the roller will now be (usually) below the black roller a bit.
8. NOW we adjust the mixture on the carbs. Set all low speed needles to about 1 1/4 turns out from lightly seated. Do not force as this will damage either the needles or the seats.
8A. With the engine idling in neutral, turn each the needles in equally about 1/8 turn at a time. Give the engine a couple of seconds between each adjustment to stabilize. Adjust until the engine either "sags" or stalls. Note this setting.
8B. Now go the opposite direction. Adjust until the engine runs rough, burbles, or stalls. Note this setting.
8C. Set all needles to the average between the two settings: That is, for example, if it stalled at 3/4 turn out and burbled at 1 1/4 out then set all needles to 1 turn out.
8D. Readjust idle speed to 700-750 RPM.
9. Take the boat out on the water and do a "hole shot"--Full throttle acceleration from a stop. If the engine "sags" then recovers and picks-up it is too lean. Open the needles about 1/16 turn at a time until the engine accelerates with no hesitation.
If the engine sputters or coughs or burbles, then clears itself and accelerates, it is too rich. Close the needles about 1/16 turn at a time until the engine accelerates smoothly.

10. I can NOT stress this enough! NEVER set the low speed needles less that 1 turns out no matter how poor the idle or acceleration. To do so will run the engine too lean and detonation and melted pistons at or near full throttle operation will result.

Thank you! Have this printed out and taking with me as immediate plan for when I get to lake tomorrow. Optimistic for success!

 

[Tassie 1]

Look for a GOOD Chrysler manual as well, as your Force is a Chrysler motor with a " new " name.