Problems with cold start....

[dc in ms]

I have a 1978 175 HP 90 degree V6 #175849C.<br /><br />The spark test seems adequate with blue spark 7/16th inch and consistent on all six cylinders. <br /><br />The timing has not been set properly with a timing light. However, I have the idle adjustment screw set where it has fired and run in the past. This was done by trial and error...crank...adjust...crank..adjust...until it cranked. Once it cranks, I let it run for a while with water muffs. Upon restart, while warm, it fires right up.<br /><br />The next day it does not start...I spray "quick start" into carb and it might or might not fire. I continue until it floods and end up frustated.<br /><br />If I pull plugs (which are always wet-wet), clean and dry them, turn engine over a few times with plugs out, then replace, more often than not it will start. <br /><br />Again, when it is running it sounds like all is well. The timing does need to be set though.<br /><br />I have champion plugs UL-77V. They look new but are atleast several years old. I have considered new / different plugs. I have considered pulling carbs and checking float valve and needle.<br /><br />What advice do you have?

 

[ob]

Re: Problems with cold start....

#1 starting fluid is not recommended in a two stroke outboard.Use a spray bottle with some premix if needed.#2 have you run a compression test on all cylinders?# What is your exact cold starting procedure?If the primer ball is pumped up until firm and the carb chokes are working there should be no need to spray fuel mix into carb throats,unless the carb orifices are fouled.Since you at least had this engine running for some time on the hose and it seemed to run smoothe the carbs may not be severely fouled.However ,bare in mind that running with no back pressure on the exhaust(on hose)is not a good indication of whether the engine will perform in water and in gear under load.Compression numbers would be a good starting point to insure the health of each hole.

 

[dc in ms]

Re: Problems with cold start....

OB, <br /><br />Recent compression test: 5 cylinders at 110 psi and 1 cylinder at 100 psi. I have not done a leak down test.<br /><br />Cold starting procedure: Initially I place warm up lever in up or start position. I do not choke initially. Ater several unsucc. attempts to crank I will then spray quick start...may fire may not...then I will move warm up lever back down to run position and try...may or may not fire...then I will choke...by now it smells flooded...<br /><br />I have best luck starting by: pulling plugs, drying, reinserting, placing warm up lever in full down or run position and crank...adjust idle screw..over and over till it fires...usually a few minutes.<br /><br />Nothing works consistently.

 

[ob]

Re: Problems with cold start....

Compression numbers look good.Cold starting should be performed by first pumping up the fuel primer bulb until it is completely firm and will push no more fuel with a moderate squeeze.This will insure that each carb bowl is filled and that all needle seats are seating.If you can continue to push through fuel with the bulb and it never gets completely firm before cranking,you have a fuel leak or one or more of the carb float needles are not seating.Once the bulb pumps up firm,lift the fast idle lever all the way up and crank until engine begins to fire.As soon as it starts lower the lever to maintain around 2000 rpm for several seconds and then finally all the way down.<br /><br />Once you get the idle speed screw set where the engine will run smoothe ,there should be no other need to mess with it.Doesn't that engine have a push (solenoid)choke ignition switch for cold startup?

 

[reeldutch]

Re: Problems with cold start....

idle speed screw have to be set in the water with the boat unrestrained in gear.

 

[emdsapmgr]

Re: Problems with cold start....

Am not sure that you are using the right sequence for starting. I always prime the bulb till it gets hard, raise the warm-up lever, then depress the key (to choke) and turn key to start. Be sure that when the warmup lever is advanced that the carb linkage opens the carbs slightly. Also, when you depress the key for choke, that the solenoid causes the choke butterflies to close. Possible that you have a bad choke solenoid.

 

[OBJ]

Re: Problems with cold start....

In addition to ob's procedure, after raising the start up lever, I would use the choke for the initial crank on cold startup. IF all is correct, the engine should fire. Then you can release the choke.<br /><br />I would also be interested in knowing the last time the carbs were overhauled and a sync and link done. What color is the float bowl gasket?<br /><br />The UL77V plugs are the correct plug. If they are several years old, replace them.

 

[dc in ms]

Re: Problems with cold start....

I do have a key activated choke which unfortunately doesn't work because the linkage is broke...I can manually choke. <br /><br />I don't know when carbs were last rebuilt. I don't think it has been too long ago because they are very clean inside and out and the gaskets appear to be fairly new. <br /><br />I have adjusted all links according to instructions in shop manual...throttle and choke valves appear to be in synch...cam mark aligns with follower roller...<br /><br />My question...how much "open" should the throttle valves be when in the warm up or start position?<br /><br />I think what I will do on next cold start is to depress bulb until firm and then some and then check for fuel leaking into in carbs. If no leaking into carb I suppose this would mean that the needle valves are working properly. Correct?<br /><br />I will place warm up lever in start position. I will verify that throttle valves are slightly open prior to start attempt.<br /><br />I will choke and crank until start.<br /><br />Anything else I need to consider?

 

[ob]

Re: Problems with cold start....

If you leave it in manual choke for too long while attempting to start the engine cold ,it will flood out.That's why they put the choke position at the touch of the starter switch ,so once the engine fires ,you can intermittedly bump the switch in which in turn intermittedly activates the choke flap until engine settles out and will idle with no choke.It's a "feel" thing.Having to move back and forth from the manual choke lever (on engine)to the start controls will take even more of a "feel" thing.

 

[dc in ms]

Re: Problems with cold start....

Thanks OB. <br /><br />I think I can rig a link up without to much trouble...this will be my next project. This will allow me to better control the start procedure.<br /><br />By the way, my woodruff / shear key keeps breaking and I feel sure it's because I am not torqing it down real good....it's a little greasy in the area also. A friend said to use the "red" Loctite on it. How do you feel about this. Any advice on this type of recurring trouble. I know this is a new and different question but this is my last post on this particular problem.<br /><br />Thanks

 

[OBJ]

Re: Problems with cold start....

DC....which part of the choke "link" is broke? Is it the sprung wire that goes from the choke plunger to the choke lever? If so, you can get this part from ishopmaring. BRP no longer carries that part. You can find the site...ishopmarine.com and follow the prompts.<br /><br />It would save you a lot of running back and forth and help with engine start up.<br /><br />EDIT: Make sure the flywheel hole and crankshaft are clean and dry. Torque the flywheel nut to 100 > 105 ft lbs. If the key keeps shearing, you may have to relap the two together using light grinding compound. Not a big deal and makes a difference.

 

[ob]

Re: Problems with cold start....

Which shear key are talking about?The one that contains the flywheel?<br /><br />If so,this is likely part of your cold starting issue.Before they shear,the flywheel is out of position with respect to igntion time.