Help?? with a 2000 yr johnson 25 engine tiller

[jaxsadie]

So I got this boat at a great deal and was told it never have had any problems....... I should have known better oh well. So the engine starts easy but when you run it up it has major hickups. You can reach about half throtle then it starts. So I put it in Neutral and ran the rpms up to clear it out, then tried again and it was a bit better but not much. so I ran it at half throtle for about 15mins then tried, and finaly got it up to plane......but could hear small misses while going WOT. So we took it in home. The first thing that I tried was to empty all the fuel in the tank and the water sep. filter, then put new fuel and hit the water again It didnt work and seemed to be a bit worse. Lets see how I can tell you how it sounds hmmmmm well take your throtle arm and while it is running push it to full then back down as fast as you can over and over. yeah thats it. It reminds off my old car I had as a kid that when you reach a certain point on that old two barrel carb it would start to miss bad. Thanks for all your help!

 

[jbjennings]

Re: Help?? with a 2000 yr johnson 25 engine tiller

Well,
I'll give it a try......

If it's missing badly and sometimes runs cleanly at wide open throttle (WOT), but surges, it could be a coil going out. You can get a spark tester to see if you have equal spark on both cylinders. Spark should jump at least a 1/4 inch gap on a $6 autozone spark tester.

It could also be a fuel problem. Try pumping the primer bulb on the fuel line when it's giving you trouble. If it smooths out and runs nicely, your fuel pump could be bad, your vent on your tank could be closed, your check valves in the hose primer could be bad, or your carb. could be stopped up. Run it and pump the primer bulb and report the results.

IF the boat has been sitting unused for a while, cleaning the carb. is a good place to start.
It's not that hard. Get a can of spray carb cleaner, take off all the plastic parts and all the jets and such. Then blow out all the tiny passages----every single one of them. Pay attn. where the parts all go. Have a carb. kit handy to use to replace bad gaskets.
You should probably put a new water pump impeller in it to be sure that it's not on the verge of going bad. It's made of rubber and doesn't last forever.

The more descriptive you can be as far as fuel, spark, and how it runs, the easier it is to help.
good luck,
JBJ

 

[jaxsadie]

Re: Help?? with a 2000 yr johnson 25 engine tiller

I forgot to add that I did pump the bulb while having problems and it did not help. A spark checker will be the next thing I get. I looked at the fuel lines and they seem to be a bit old so I will change these next. I bet the carb does need a good cleaning. So doing a carb kit is easy? I have built a few car carbs and small gas carbs, but never a boat carb. And you are correct about the impeller I noticed that it was not pumping good at the end of the day during idle. So that also is first on my list. Is the impeller a hard change? I guess I should get a manual

 

[jbjennings]

Re: Help?? with a 2000 yr johnson 25 engine tiller

I find it really difficult to rebuild a car carburetor, so if you can do that, an outboard carb. will be as easy as pie.
Impeller is easy also. Just be careful to remove the black cone-shaped keepers from inside the acorn nuts that connect the shift shaft coupler which is behind the water intake screens in the lower unit.
It sounds like a coil or powerpack--hopefully a coil which it sounds like. If you're getting weak spark, swap the coils and see if the prob. follows the coil.
Later,
JBJ

 

[jaxsadie]

Re: Help?? with a 2000 yr johnson 25 engine tiller

Thanks so much for your help