1986 Evinrude 125 V4 won't go beyond 2500 rpm

[BCcoast]

Hello everyone,

I've just joined the forum today, as I had an engine problem yesterday while on a cruise going up Indian Arm on the BC coast. My 120 hp V4 Evinrude (1986 model CE120TLCDC) was running great--except for idling in neutral, where it would run for a couple of minutes before sputtering and shutting off--and I didn't take it up beyond 4000 rpm during the entire 1-hour journey because the speed on my 16 1/2' Malibu was beyond my comfort zone. In any case, when I began the return journey, the motor started to shake and ping when I tried to take it up to a good planing speed; it would only run well to 2650 rpm before shaking/pinging and would not go any higher in rpm. I know that the fuel is clean and fresh--I had completely drained, flushed, and refilled the fuel tank with fresh 50:1 mix--and the plugs and plug cables are less than a year old. Any thoughts from folks here on what my first step should be? Thanks in advance to anyone replying!

 

[Bosunsmate]

Re: 1986 Evinrude 125 V4 won't go beyond 2500 rpm

Have you tried priming the fuel bulb while running to see if that fixes it?
It could be a failing fuel pump.
Would it idle ok before spluttering after a couple of minutes?

 

[Bosunsmate]

Re: 1986 Evinrude 125 V4 won't go beyond 2500 rpm

Have you tried priming the fuel bulb while running to see if that fixes it?
It could be a failing fuel pump.
Would it idle ok before spluttering after a couple of minutes?
Put your hand on the heads check they arent too hot that you cant have your hand on them for at least 5secs

 

[BCcoast]

Re: 1986 Evinrude 125 V4 won't go beyond 2500 rpm

The idle wasn't that smooth--a 'miss' every 10 seconds or so (you could see a dip in rpm on the tachometer), but at high rpm it had smooth power. I'll try priming the fuel bulb tomorrow and see it that changes things--thanks! I did try touching the heads and they weren't overly hot--at least not what I would consider that to be.

 

[malta]

Re: 1986 Evinrude 125 V4 won't go beyond 2500 rpm

The idle wasn't that smooth--a 'miss' every 10 seconds or so (you could see a dip in rpm on the tachometer), but at high rpm it had smooth power. I'll try priming the fuel bulb tomorrow and see it that changes things--thanks! I did try touching the heads and they weren't overly hot--at least not what I would consider that to be.

I had a similar problem with my evinrude 200 - i would reach about 3,000 rev and it would just die... no sputtering or shaking through. The problem was a simple one to solve - fuel starvation because of a corroded / aged fuel line that has collapsed, and wasn't allowing enough fuel through. Not completely sure its the same thing but worth a try investigating - its an easy fix.

 

[BCcoast]

Re: 1986 Evinrude 125 V4 won't go beyond 2500 rpm

Hello again,

I tried priming the fuel bulb while it was idling and it may have changed the idle somewhat for the better, but I did notice that one cylinder bank was significantly hotter than the other--how much I don't know, but I couldn't keep my hand on the starboard bank for a full 5 seconds, whereas the port bank was only warm. Now the boat isn't standing on a level piece of ground (leaning down towards the port side on my hilly front lawn), so that may affect things.

One other thing I found was that the voltage regulator doesn't seem to be working--when you rev the engine the voltage climbs, eventually going up to 15 volts, so I think that at the very least I need to replace the voltage regulator ...

 

[Bosunsmate]

Re: 1986 Evinrude 125 V4 won't go beyond 2500 rpm

You need to look into the starboard bank temperature further as if they get too hot you can do quite some damage, like breaking the rings or warping the cylinder head and getting water into the cylinder. Ive found the starboard bank does seem to run a bit hotter on these but not as much as what you describe. The paint on the head will often turn dark brown when its overheated.

Try putting it on a level ground and see if it fixes it. If not you will need to check your thermostat for that side of the engine. Replace the impeller if you havent for a year or two. Also check that when the brown wires from the temperature warning senders are grounded that a warning horn goes off on the control up front. They have a blackrubber sleeve which can be moved up the wire exposing a metal contact breaker which if contacted to a bolt on the head to complete a ground circuit will make the horn go.

 

[BCcoast]

Re: 1986 Evinrude 125 V4 won't go beyond 2500 rpm

Thanks for your ideas, Malta and Bosunsmate!

I replaced the thermostat on the starboard side today only to find that it is still running as hot as before. After some brief pouting/frustration, I decided to run the starboard side without a thermostat to find what would happen to the temperature--success; this bank ran at the same barely-warm temperature as the port-side cylinder bank. I'll take it out for a run on Indian Arm over the next couple of days, just to find out what happens.

 

[Bosunsmate]

Re: 1986 Evinrude 125 V4 won't go beyond 2500 rpm

Be careful as if it runs fast when too cold you can have a cold water seize which sucks too.
Ease it up gently.
Your port thermostat could be stuck open keeping that side cold, or your starboard water deflectors might have gone or there is crud built up on the cylinder walls etc
You could try changing the impeller.
Take out a camera if possible and record the miss if it happens again. Note if it happens at start up or if it only happens when hot

 

[BCcoast]

Re: 1986 Evinrude 125 V4 won't go beyond 2500 rpm

Problem solved--I think ... I took the boat out on Indian Arm today and the engine ran great--no going into 'slow mode'. Yesterday, I decided to inspect the thermostat on the cylinder bank that wasn't getting hot and found that the thermostat was loose in the housing; its anchoring stud was broken off and the broken piece was lodged in the thermostat housing cover, right in front of the water intake!

After finding the likely problem, I installed the 'old' thermostat from the starboard bank on this side and the new thermostat I had purchased on the starboard. When I started the motor I could tell right away that things were as they should be--both cylinder banks around the same temperature and the water streaming out of the tube at the base of the powerhead (after the thermostats opened) was warm. I checked this when out on the open water today and temperature was the same--warm. In any case, it was a great day on the water and the motor really moves the boat--too fast for me to ever take it up to full throttle, but it's good to know its there if you need it! Now if I could only do something about it going through so much gas ... ; )