1985 150 Motor stalling when engaging throttle

[SirEnvy]

Hey everyone, new to the forum and figured this was the place to go since Google tends to me to this site for help. Anyway, I bought a 1985 150 Motor, and took it to a mechanic who did a compression test for 50 bucks and told me it was solid. So he hooked up the motor to my boat, all controls fit, so I was lucky there. After towing this boat for an hour I launched it and the thing dies when I engage the throttle. Ive searched up and down these sites and alot of people have the same issue, and it tends to be a fuel thing or carbs(which the mechanic told me he checked them out). Most of these forums dont have the ending results on what the guy/gal did to fix it.

About the mechanic, hes a good mechanic and honest. My buddy had his powerhead rebuilt about 4 years ago, and hasnt had a problem since. But I could take it back, but he would charge me labor anyways. since he told me everything is good, it must be something stupid.....

I changed the plugs, and clean the motor with degreeser, and covered electronics. The electronics that I couldnt cover was quickly sprayed with WD40 and then sprayed with electric cleaner.

 

[oldcatamount]

Re: 1985 150 Motor stalling when engaging throttle

Try doing a spark test to see if all cylinders are getting a good strong spark. You can get a spark tester at any good auto parts store and they don't cost much. It sounds like you may be dropping a cylinder or two and a spark tester will show you that. Another issue to consider is a carb cleaning/rebuild. Have you ever done anything like that before? If not, it's not really difficult and you won't need any special tools.

 

[HighTrim]

Re: 1985 150 Motor stalling when engaging throttle

Id agree to start by verifying that you are running on all cylinders. May have idled fine on muffs but under load things are very different. An inline spark tester as mentioned above would work, with the gap set to 7/16 of an inch. It should jump that with a bright blue ZAP!! If it doesnt, start by swapping the coil with one of the coils from a cylinder that was sparking strong. If that doesnt solve it, we will have to dig deeper.

I get confused by these mechanics that say that they "looked" at the carb and it was fine.

Other things to check are that the timer base moves smoothly without sticking when you advance the throttle, take the airbox cover off and ensure that the throttle plates are parallel, and finally ensure that the timer base starts it travel before the throttle plates start to open.

Let us know what you find or if you need any further explanations of this. By the way, you could have bought yourself a compression gauge for less than 50 bucks, done it yourself, and had the gauge for future testing. Very easily done with a little help for your first time.

 

[SparkieBoat]

Re: 1985 150 Motor stalling when engaging throttle

spark or fuel or compression..almost every time

 

[emdsapmgr]

Re: 1985 150 Motor stalling when engaging throttle

All good comments. Once you determine the spark is solid on all 6 cyls, you may need to overhaul the carbs. With today's crappy fuels it is easy for fuel to dry up in the fuel passages inside the carbs-blocking or restricting fuel flow. A complete carb teardown is necessary. Make sure you pull all 6 jets out of each carb and inspect them. A typical aerosol carb cleaner will dissolve dried fuel in the carb passages.

 

[SirEnvy]

Re: 1985 150 Motor stalling when engaging throttle

I appreciate all of the responses. I replaced the spark plug to coil pack wires, and it idles better. However, I called the mechanic he worked on and he wants to tell me its bad fuel again, which would be one heck of a coincidence. So he referred me to a local guy who is coming out today to check it out. I will respond with more detail tonight with what he said.

 

[emdsapmgr]

Re: 1985 150 Motor stalling when engaging throttle

An offbeat queston: Did you happen to take a fuel sample to test for water in the fuel tank? An engine will run with water in the fuel, but will have no power.

 

[SirEnvy]

Re: 1985 150 Motor stalling when engaging throttle

Well, I am glad I opened up this forum because by my surprise and many others, is that apparently, underneath the flywheel there is some kind of linkage, and it was disconnected for some reason. I had a mechanic come out and basically solved the problem.

 

[boobie]

Re: 1985 150 Motor stalling when engaging throttle

Was that the linkage to your timer base?

 

[HighTrim]

Re: 1985 150 Motor stalling when engaging throttle

Ill bet it was

 

[SirEnvy]

Re: 1985 150 Motor stalling when engaging throttle

Was that the linkage to your timer base?

I beleive so, the mechanic came out to my boat while I was at work, and I couldnt quite understand what exactly it was, but I believe it was the linkage, something VERY minor. This should be on the checklist for this common problem.