1984 150hp evinrude will not accelerate

[lk93]

I have recently bought a 1984 venture bass boat with a 150 hp Evinrude. When I test drove it seemed to run fine. I took it out about a month ago and today. Both times the motor would bog down on acceleration and a couple of times it even died. Supposedly the motor and carbs were rebuilt within the last few years. The coils were also replaced and maybe some of the other electrical components. Pushing the key (activating the choke/primer) will cause the motor to take off and once on a plane will run normally. We have also found out that when one person sits on the front deck it will plane out and run normally.

I have tested the compression on all cylinders and it was between 80 and 90 psi on all which seems a little low to me. I was thinking it might be a carburetor adjustment, but there are no adjustments available. Due to the weight situation with one person in the front I was thinking it might have something to do with the prop. Sometimes when it is first started it smoke heavily. The smoke does have a blue tint, like the oil I am using. When I got home today I pulled the plugs and they all had what looked like oil on them. Any help would be appreciated. Thanks.

 

[racerone]

Re: 1984 150hp evinrude will not accelerate

Pushing the key in activates an electric valve ( primer ) ----this squirts fuel into the motor.----This fuel bypasses the carburetors.-----To me that clearly indicates a problem with carburetors.

 

[Bosunsmate]

Re: 1984 150hp evinrude will not accelerate

Are you using a vro pump? if not what ratio a you premixing at?

 

[emdsapmgr]

Re: 1984 150hp evinrude will not accelerate

Agree. Pushing in on the key does inject extra fuel into the carbs. If it runs better when the key is pushed in, it's probably running lean. Could be a bad fuel pump. Next time out, take a buddy with you. When running, have him constantly prime the fuel hose bulb. This will force extra fuel into the carbs. If the engine runs fine (at WOT) as long as you constantly prime the fuel hose bulb-then your problem is lack of fuel to the carbs. Could be a weak fuel pump, bad fuel hose bulb ball valves, bad anti-siphon valve in the tank, etc. That engine comes with low compression (bathtub) heads, so your compression is normal. That engine is a 2-stroke and will smoke somewhat when first started.

 

[lk93]

Re: 1984 150hp evinrude will not accelerate

I initially thought it might have something to with the carbs as well, but the thing with sitting in front confused me. It does run fine once on a plane. (I don't need the primer on a plane) I will try the pumping the bubble thing hopefully this weekend.

I am using the built in pump for oil.


Thanks

 

[emdsapmgr]

Re: 1984 150hp evinrude will not accelerate

If it runs ok at WOT, the fuel pump is fine. Have you verified the sync and link (carbs/ignition advance relationship?)

 

[lk93]

Re: 1984 150hp evinrude will not accelerate

I just went out to the garage and checked the movement between the throttle and timing advance. I am not sure exactly how it is supposed to work, but the pickup for the timing under the fly wheel did not even move. I assume this is a problem. I am also not sure what is supposed to move the ignition part, I am thinking it should be spring loaded, but I am not sure. With the control lever in wide open position I can move the advance with my finger but it does not move by itself. I have not yet taken anything apart, I was just wondering if I could get any advice, and make sure this is the problem before taking it apart.

thanks again

 

[racerone]

Re: 1984 150hp evinrude will not accelerate

Sounds like a linkage fell off.-------Inspect it closely.-----Look at the top of the throttle arm as that is where it connects.----Pictures sure help in this situation.

 

[boobie]

Re: 1984 150hp evinrude will not accelerate

Sounds like your timer base is sticking and needs to be disassembled and lubed.

 

[lk93]

Re: 1984 150hp evinrude will not accelerate

I tried to attach some pictures, but it didn't work. I loosened the bolt that the throttle and timing linkage piviot around and sprayed some lubricant on the spring and joint. It seemed to help some. I am not sure what the timing base is I would assume it is the part up by the fly wheel. What is involved in disassembling it. The linkage seems to be hooked up.


thanks

 

[emdsapmgr]

Re: 1984 150hp evinrude will not accelerate

Make sure the spark advance rod is properly connected (seated in the two ball joints) between the spark advance lever and the timer base under the flywheel. Also, it's not unusual for the lubricant under the timer base to solidify after many years, making for slow movement of the timer base. You'll have to pull the flywheel in order to get at the timer base-to clean and re-lube it.

 

[lk93]

Re: 1984 150hp evinrude will not accelerate

Sorry I have not responded recently. Between the weather and work I have been busy. I think with a bit of lube it seems to work. I will have to test it to be sure. I appreciate your help.


Thanks again :joyous: