1971 merc 1150 help!!

[mwinchel]

Hey Everyone,
i am going to try to make this short so i can narrow my problems down. Just a little background info is i have owned it for 2 years, its on a 14.5 foot tri haul boat. Some say i should fly with this motors others say it is a tri haul that is all you will get. this boat acts up on occasion. the normal load is 5 people with a cooler weighing close to one more person. i don't tube or ski i just go to a hangout place and then back to the dock. Ok about the motor good condition have good compression on all cylinders, just re wired the whole motor. took the distributor cap off it looks good, and i have gone threw the carbs and made sure everything looks fine, and replaced the pump diaphragms. this motor will cut off if i stay at wide open for any length of time or if i hit a big wave. the motor bogs down to where i will pull it back to neutral and then start again some times it will cut off. Ok the last thing is i took it out the last time this year and got stranded 1000 feet from the dock the first time ever the boat has not cranked up. i would start to give it gas and instantly the motor would bog and it would cut off not wanting to crank. i have not looked at this boat since i brought it home from the lake. i have not changed the plugs in 18 months or so also. any suggestions i want to try over the winter to get this thing running perfect for next summer let me know thanks and sorry for the short novel.

 

[Paul DuLaney]

Re: 1971 merc 1150 help!!

The last inline I had was a 135 and it had champion plugs in it .I put ngk in it and it ran a lot better but I still had to clean them every so often or replace them. I went through about two to three sets a year on the average,but around here the lakes are shallow and we have to do a lot of idling so that can make a difference.Also I installed an inline fuel filter and was surprised at the junk it stopped from going to the engine including moisture.If you don't have one on you might want to.Hope it helps,good luck

 

[Chris1956]

Re: 1971 merc 1150 help!!

That was a bit difficult to follow. First of all that boat should go 45+MPH with that motor. It is likely quite over the Max HP for that hull.

OK first check to see that all plugs are firing. Pull 'em out and look at them. They should all be brown ash and maybe some oil. If any are clean, you may have water infiltration. Install the plugs and start it up on a flusher. Remove the cowling and see if the plug wires are arcing to the block. Especially #5 and 6.

The next time you are at full speed, have someone pump the primer bulb and see if that keeps you at high speed. If so, rebuild the fuel pump. If you lready rebullt it, check the fuel line and filters for restrictions, especially the antisiphon valve on the built in fuel tank.

If hitting a wave causes the motor to bog down, check the white and red wires on the switchbox for loose connections. Also check the quick disconnect elec plug for bad contacts.

 

[mwinchel]

Re: 1971 merc 1150 help!!

Hey there what is the quick disconnect deal where is it at. I will check into all of this. I was just reading a thread on stators could it be my stator? i have never been stranded till the very last time this year. usually it starts back up and will go again. i have had someone pump the bulb when is starts to go but that does not help any. i have replaced the fuel pump diaphragms, and the fuel line and bulb.

 

[Chris1956]

Re: 1971 merc 1150 help!!

The quick disconnect is the large black plug on the starboard side of the motor. Sometimes the wiring breaks inside the plug and you get intermittent power to the ign system. If you have a distributor, then all your stator does is charge the battery. it plays no role in the ignition.

 

[mwinchel]

Re: 1971 merc 1150 help!!

could it be anything with my coil?

 

[Chris1956]

Re: 1971 merc 1150 help!!

It is not too likely that it is your coil. The motor shutting down after a wave hit is likely electrical. The motor shutting down at WOT is either fuel pump or some strange electrical failure.