boat running rough and dieing at low speed

[Karla45]

My boat drives fine unitl i slow down to 10 miles or less then it runs rough and will eventually die. When i go to start boat i cannot get it to rev up so i can warm it up, i do not want to rev up real high just enough to get it going really good. Also, after i start the boat and give it some gas it will die. It can be really hard to start once it starts dying on me. Should I adjust the throttle first before trying to adjust a carb. I always pump primer bulb before starting so i know this is not the starting problem. the carbs have been cleaned recently. I have 1989 force 85HP

 

[Jeremy90bay]

Re: boat running rough and dieing at low speed

Are you starting the boat in the fast idle position on the controls? Most controls either have a button to disengage the shifter or the control handle pulls out and goes forward.

 

[Karla45]

Re: boat running rough and dieing at low speed

not sure what you mean? I pull handle out and then down, pump bulb, choke, it will start okay like this but once i move the handle back up and then forward it dies. Eventually I will be able to run the boat but it takes alot of restareting. One problem i noticed is that when I pull handle out and then push handle forward it will only go one speed and not able to run the engine a little higher in order to warm it up before running the boat. I do not know why i said it is hard to stop, it is more like it is harder to keep it from dying so I can go forward and it dies on me when i slow down and runs rough.

 

[further]

Re: boat running rough and dieing at low speed

Do you have a tach? What is your rpm at idle? Should be btwn 700-800 rpm

 

[maxum_man]

Re: boat running rough and dieing at low speed

...in forward gear

 

[john from md]

Re: boat running rough and dieing at low speed

When is the last time you cleaned your carbs or decarbonized the engine? I suggest that you clean your plugs, decarb a couple of times and see what happens. Decarb procedures can be found in the FAQ at the beginning of the maintenance forums.

John

 

[Karla45]

Re: boat running rough and dieing at low speed

carbs have just been cleaned.

 

[Karla45]

Re: boat running rough and dieing at low speed

i do not have a tach where can i buy one that does not have to be installed on boat?

 

[john from md]

Re: boat running rough and dieing at low speed

Look for an inductive tach on ebay. There are many makes of handheld tach dwell meters for sale. I bought a Suntune for $10 and it has been working for years. You will find Craftsman, Sears, Snap On, MAC etc., just make sure it is inductive so you just clamp the pickup on the number one cylinder lead.

John

 

[Karla45]

Re: boat running rough and dieing at low speed

so once i get a tach what am i supposed to do if numbers are not right, adjust idle, carb?

 

[jason32038]

Re: boat running rough and dieing at low speed

Idle speed should be set in neutral 750-800 rpm. If it dies when you put it in drive you need to adjust the link rod with the 2 plastic ends. Once you get it to shift into gear without dying...shut the engine off and go to full throttle position and make sure the carb shutters are level and wide open. Recheck timing. OR to start off with the engine off you can go to full throttle position and make sure the throttle shutters are level...if they arent then adjust them with the linkage adjustment..then set idle in neutral and it should be fine when you shift into gear. I dont know if this is proper procedure but the second option worked for me.

PS...you might have other problems other than idling problems like a blown head gasket . Check the idle screw on the engine and see if it's still tight and doesnt turn by hand. If it's still tight i'd look elsewhere. Check the timing linkage that connects to the towershaft. I seen in a different post that the plastic piece broke and the trigger was not moving to advance the timing.

 

[john from md]

Re: boat running rough and dieing at low speed

You really need to buy a Clymer Force Outboard Shop Manual first. Then you need to set up the carb/timing syncronization. It cannot be done piecemeal as the two are mechanically interconnected and you must start from a base line.

To correctly set your idle, the boat must be in the water tied to the dock with the trottle in forward.

If you follow the manual, your boat will run properly assuming you don't have any problems with CDI modules, fuel pump etc.

John