1981 merc 50hp hard to start

[driftmaster]

In order to start my motor I have to give a couple<br />of squirts of fuel mix to get the motor to fire.<br />If I do not, I have to crank till the battery is nearly dead. After running for a bit it will start up first crank. The longer it sits the harder it is to start again. Here are some of the motor specs and the parts I have replaced.<br /><br />1981 Merc 50hp 4cyl<br />Compression 130, all 4 cyl<br />Complete carb rebuild<br />New primer bulb/fuel line<br />New plugs<br />Appears to have strong spark, all plugs firing<br /><br />Any ideas appreciated

 

[dakk1]

Re: 1981 merc 50hp hard to start

driftmaster<br /><br />Wonder why the choke doesn't work? My '85 Merc 150 cranks fine when I prime the bulb and hold the choke for about 10 sec then hit the switch. If I just try to crank it without choking I think it would spin for a week and never fire. Seems you really have to load these older Mercs up with fuel first crank of the day.

 

[andrewkafp]

Re: 1981 merc 50hp hard to start

1981 elec start should have an electric choke solonoid located above the carbs. You should hear a "Click" when you engage it. No click =No choke.<br />To test it, run a test wire from the positive battery terminal to the choke positive. Careful no to short it anywhere. If it engages, it's the switch. If not, it's the soloniod and it will be hard to start cold without the choke.If it's the choke, get someone to engage it manually, by grabbing the linkage and closing the butterflies. the see how it starts.

 

[rdmcphe]

Re: 1981 merc 50hp hard to start

I have the same motor. It starts very reliably for me. Here's what I do...<br /><br />Cold Starting Procedure<br />=======================<br />1. Attach fuel line and squeeze primer bulb until firm (usually 3-4 times for a dry carb).<br />2. Press the throttle only button and advance the throttle to the first stop and then a bit more (about 10 degrees past the first stop)<br />3. Turn the key to start. It fires within 1-3 seconds. <br />4. Push in the key momentarily to activate the choke if it sounds like it is going to stall. A clicking sound is heard when you push in the key.<br />5. Adjust throttle to not exceed 2000 RPM. <br />6. After about 30 seconds return the throttle to neutral. It should idle normally.<br /><br />Warm Starting Procedure<br />=======================<br />1. Make sure it is in neutral and turn the key - starts very quickly.<br /><br />I hope this helps.<br /><br />Russell

 

[andrewkafp]

Re: 1981 merc 50hp hard to start

Do either of your motors look like this ?<br />With Blue band and silver text ???<br /><br /> http://au.photos.yahoo.com/andrewkafp

 

[driftmaster]

Re: 1981 merc 50hp hard to start

I appreciate the prompt respose. The choke does work and you can hear the click. I just checked the choke and it appears the butterflies are closing but not the whole way, probably a 45 degree angle. I am sure this would affect the mixture quite a bit. Sounds like it could be my problem. Any tips on choke/butterfly adjustment?<br /><br />Thanks driftmaster

 

[driftmaster]

Re: 1981 merc 50hp hard to start

Andy,<br /><br />That is the motor I have. Looks exactly the same

 

[andrewkafp]

Re: 1981 merc 50hp hard to start

Driftmaster.<br /><br />Don't know where you are located, but a Clymer manual would be handy for you. I am in Australia and they are hard to get and pricey here, so I photocopied one. They will tell you how to adjust the choke linkage, but I would say, by looking at mine that it would be easy and just mechanical. It's important that the butterflies close, as these motors like to be "choked to death" as one iboats member said.Try to find 12footer (He has affairs with Mercs jkg) or sharkcat from perth, who is also pretty cluey.

 

[ledgefinder]

Re: 1981 merc 50hp hard to start

Drift, that does sound like your problem. You do have to get the butterfly's slamming 100% closed, 99.94% won't do it. I don't think there's an adjustment on those (at least there isn't on the 1978 & 1974 50hps), something must be bent up in the linkage. Should be adjusted so that the solenoid 'wants' to pull it past 100% closed.

 

[kohath]

Re: 1981 merc 50hp hard to start

Amazing what those little choke butterflys will do. I just got my boat ready to take out after 4+ years. I must have forgot about pushing in the key to set the choke. Without the butterflys closed, no way would the motor start, not even a pop. And I tried quite a bit, using starter fluid, WD-40, etc. It would start with the started fluid, but stop once it burned it off. Once the butterflys were closed, and they do completly close the carberator throught, the motor immediatly fired up. Every time. My problem was not with the choke, but the operator, me. I don't know much about the 2 stroke engines, but I suppose the choke helps the engine suck up extra fuel in there somewhere to start it and help it to keep running.

 

[andrewkafp]

Re: 1981 merc 50hp hard to start

Mine has the black button on top rather than the key push technique, but the principle is the same.Last week, the button was playing up and the choke did not engage. It took 5 minutes to start.<br />I fixed the button and next time (1 week later) straight up...<br />Driftmaster.. take a look at Kohath's chrysler pics here...<br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=17;t=032818

 

[rdmcphe]

Re: 1981 merc 50hp hard to start

Andy, <br />My motor looks just like the one in your photos.<br /><br />Russell

 

[driftmaster]

Re: 1981 merc 50hp hard to start

I am going to adjust/fix the linkage tomorrow. Hopefully it does the trick. I can't believe I never checked the choke operation. I will post the results. <br /><br />Thanks,<br /><br />Driftmaster