hard start for '81 25 HP Johnson

[katz]

I have an'81 25 HP Johnson with a manual start & manual choke. Once I get the OB runing she runs like a top howvere it's the starting that I have problems with. What I have to do is take the cover off, soak a rag with fuel & cover the air intake on the black plastic air intake. THat's the only way to get it started. But once it starts & warms up, it's great. If it cools, I have to do the rag trick again.Some of the things I have done so far to rectify the problem, I have placed new plugs in the engine, I have taken it to 2 different shops & they both say it runs fine, I have done a carb kit, I have changed the fuel connectors on the line from the tank to the OB & I have also replaced the electonic coil with lead for each plug. Someone on the Wooden Boat forum suggested this forum however I have had some great ideas with the WB Forum. Here are some of their suggestions;1- change the whole hose from tank to OB. 2- If I haven't stabilized the fuel, there is a chance that the carb is plugged with varnish. (If so how do I check for varnish & how do I get rid of it)3- Another suggestion that the "syncronization" between the spark advance & the throttle could be the culprit. 4- Another was the choke pivot was worn out & leaking air & not enogh vacuum to pull fuel from the main jet. the only way to rectify it was change the carb.<br /><br />I guess I'm just p****d with bringing it to mechanics & getting ripped for a pretty simple OB. <br />Thanks

 

[ob]

Re: hard start for '81 25 HP Johnson

What is your usual starting procedure?(besides the fuel soaked rag) Are you pumping the fuel bulb until it is firm and holding?Do the flaps close fully when choked.If you installed the kits properly ,I'm guessing gummed low speed passages are not the issue.Have you obtained any recent compression test numbers?

 

[katz]

Re: hard start for '81 25 HP Johnson

Usual start is that I pump the fuel bulb until full & hard. Usually some small amount of fuel leaks from the fuel line connector to the OB. Flaps do close on the choke. Only thing I haven't done is the cmpression test that you mention. Ill try to get that in the near future.

 

[tashasdaddy]

Re: hard start for '81 25 HP Johnson

try putting premix gas in spray bottle and spray directly into the carb, easier than holding the rag. and will let you know you have a fuel flow problem

 

[Silvertip]

Re: hard start for '81 25 HP Johnson

You said you installed a kit in the carb. If you didn't totally disassemble and soak the carb and make sure all the jets and passages were free of gunk and varnish, all you did not accomplish the purpose of a rebuild. If you have leaking connectors, they need to be replaced. An engine cannot suck fuel with an air/fuel leak. The engine needs spark, fuel, and air and everything needs to occur at the proper time (timing). Miss any one of these and you will have a poor/no start condition. Eliminate one system at a time and by all means, check and repair the cheap stuff first. Don't just throw parts at the engine.

 

[rodbolt]

Re: hard start for '81 25 HP Johnson

double check your choke. all your doing with the rag is creating your own choke and if it runs fine once warm all the other circuits in the carb are ok mostlikly. the choke simply creates an excessivly rich fuel mix for cold starting and once its started has nothing else to do but go boat riding.<br /> had a friend that used his 95 115 yamaha a long time by taping off the airbox inlets occasionally so it would start. I finally modified the carbs so it would work.<br /> but your description ibdicates a choke shutter not closing correctly.