Motor is "surging" at WOT

[hondakillrsx]

hey all,
The title says it all. I have a 50 horse Force that starts fine idles fine runs fine at up to about 3/4's thottle. but anything over that and the motor either looses fuel or spark. I researched here for help and came across a forum that said to pump the ball when it starts but it doesn't do it long enough to really try. I did however pump it right after it happens and it seems that the motor bog's down as if it was flooding it, so if i had a guess it would be the spark. I was going to take out a plug and see what they look like later on. any advice would be great! thanks.

Lane

 

[Crater]

Re: Motor is "surging" at WOT

sounds like the float needle is sticking. If seated correctly the flow of fuel is shut off. Maybe sticking shut a little. Run some Sea Foam through it from a gallon tank(de-carb the motor). If that don't work it may need to be removed and cleaned. 2nd is there a fuel pump?(probally not) if so maybe it's getting weak. If you dismantel the carb look especially for rubber pieces, fuel line may need replaced also. Fuel filter new?

 

[hondakillrsx]

Re: Motor is "surging" at WOT

thanks, i'll try that first.

 

[john from md]

Re: Motor is "surging" at WOT

You may have floats that are setting too low giving you a rich condition at WOT. Since you pumped the ball and the engine seemed to bog, that tends to indicate that your mixture is not lean.

When is the last time the carbs were looked at?

John

 

[hondakillrsx]

Re: Motor is "surging" at WOT

When I do a decarb, can I just but the gallon tank in the place of the other tank (ie, behind the fuel ball)? And I've only had the boat for a couple months and the previous owner said that he just had them rebuilt. But you never know if he was just being a sales man. It's been running fine up until last week. do you need any kind of special tool to check the spark to the cylinders?

 

[john from md]

Re: Motor is "surging" at WOT

Yes, you can use a gallon tank in place of the regular tank.

To check spark, take the plugs out of the cylinder, ground them using wire or jumpers to ground and have someone turn the key to start. Watch for a lot of blue sparks on each plug. Orange spark means a weak spark.

John

 

[Crater]

Re: Motor is "surging" at WOT

Search for decarb instruction here. FOLLOW Sea Foam directions for cleaning 2cyl motors, it's different for a 4 stroke and for fuel stabilization.

One more thing to reinforce Johns post. MAKE SURE you ground the plug as it may cause the CDI to fry if you don't. And remember Fuel and sparks don't mix. Unhook the fuel line, run the motor out of gas, then pull the plug to check it. Your not trying to run the motor, your only troubleshooting ignition at this point. What happens when cranking happens at idle and wot; so orange spark is bad, blue is what you want to see when cranking.

 

[hondakillrsx]

Re: Motor is "surging" at WOT

ok guys,
So I just did the spark check and it seems i have low spark on the bottom cylinder. Is this for sure a a bad coil? what else could it be if not?

 

[john from md]

Re: Motor is "surging" at WOT

It can be a bad coil or a bad CDI box. The easiest thing to do is switch the coil with one that has a good blue spark. If the problem moves, you have a bad coil, if it doesn't move, the chances are that it is a bad CDI module.

To check the output of the CDI module, go to the electrical section of the manual and check for the voltage coming out of the unit. I believe on yours, it should be 150 volts. Depending on the year the engine was made, it tells you the wires to check.

John

 

[hondakillrsx]

Re: Motor is "surging" at WOT

ok so I took her out today and she ran like a champ! all i've done to her is put a new gas ball and lines, decarbed, cleaned the carbs and cleaned the sparkplugs. I think it was the spark plugs because they seemed really dirty and might have been fouled. Thanks for all you guys' help! Lets hope it doesn't come back!