1988 Evinrude 30-HP keeps shutting down at full speed! Help Please!

Hi there everyone, I been having issues when running at full speed for about 10 seconds, then the motor boggles down, then dies. After the motor dies it takes a good 20 mins of waiting and repumping the fuel ball before it can get back up running, but it takes 10-15 hard pulls until the motor starts backup again. Motor will run fine at slow or medium speed. I have taken the motor to a Marine shop in robbinsdale twice for the same issue and each time they tell me it’s running fine, but once I hit the water it stills die at full speed. The Marine shop changed spark plug, gasket, tunes ups, and everything they do on a regular basics. So I am clueless to what is going on here, I’m familiar with cars, but marine motor is something I haven’t mess around with. Funds are running low at the moment, and I thinking its time to fix it myself. Here are my own personal thoughts as what might be going wrong:

1) The main fuel line from the gas tanks had gone bad, because the Marine shop said the motors is running great, and they used their own fuel line. Should I replace my main fuel line???

2) My buddy said “90% of the time with these smaller outboard it’s a fuel problem.” I’m thinking the fuel in my gas tank has gone bad, and installing a in line fuel filter in the main hose. Water built up in my gas tank transfer in the motor? By the way I only put Non-oxygenated fuel in my motor.<—was told to do so by Marine Shop(Robbinsdale) when I purchase the boat years ago.

3) Maybe I just need a carburetor cleaning?

4) Would Sea Foam Motor Treament be a solution?

Inaddition, my lower unit gets extremely “HOT” once the engine dies at full speed, is it normal for the lower unit to get hot?
Please help. I can’t sleep because them eye are bitting like crazy on the croix, and I’m stuck at home due to engine issues.

I’ll address each of your numbered options in order.

I’d look at two things. My first impression is that you have an air leak somewhere that’s reducing your fuel flow at high speed and adding air to the flow so the engine is starving.

IMPORTANT: Change only one factor at a time so you can isolate the problem.

1. Yes, change your fuel hose and test. It would be better to borrow one if you can, but the hose could be the source of the leaks. Inspect your hose closely for cracks at the fittings.

2. Fuel in the tank could be the issue. However!!!! It could also be the tank itself. I’ve see dip tubes crack and gaskets around the fuel fittings leak.

The best solution would be to run off a totally different tank that you know has good fuel in it AND that you know works for another outboard.

A filter is a good idea, but it won’t fix fuel that has gone bad due to water contamination or phase separation. So just adding a filter is unlikely to help in this case.

3. Let’s cross the carb cleaning bridge later. Maybe, maybe not. Test the simple factors first.

4. Seafoam = no. Seafoam is a detergent that clears blockage from fuel system residues. Even if your problem is a blockage, Seafoam is unlikely to be able to solve it on its own.

5. Need more info about your lower unit. Where is it getting hot? What part of it is hot? Describe this in as much detail as you can.

Grouse

Same exact issues with mine for the FYB this year from what it seems the same shop.

My gas fitting on the tank had a tiny crack on it, unnoticeable from glancing at it, but with higher speeds made the pressure escape through that crack. I’d imagine you might have similar issue, check the hose and fittings very carefully for cracks, as I switched tanks and was good to go.

The fact that it runs fine at wide open, then suddenly stops is throwing up a flag at me. This sounds like an overheating issue. The next time it dies like this, take the cover off it quick and see if you can touch the head. You should be able to hold your finger on it for a few seconds. It should be hot, but not enough to burn you. Is there paint discoloration on the head?

When was the last time you checked the thermostat? The impeller/water pump?

If you send me a friend request, I’ll PM you a link to another forum that does nothing but help in situations like this.

Actually it is the midsection right behind the mounting bracket. I think it is the exhaust housing. Right under the Powerhead connect to the midsection. is where it gets really hot. Now is this normal?

Do the test where you touch the head and go from there.

Basseye651 wrote:

Actually it is the midsection right behind the mounting bracket. I think it is the exhaust housing. Right under the Powerhead connect to the midsection. is where it gets really hot. Now is this normal?

How hot is hot? As in if you touched it for more than a second it would burn your finger? That’s too hot.

The outboard’s exhaust passes through the midsection and the exhaust housing on it’s way down to be discharged under water, but that exhaust is mixed with cooling water so that should keep the midsection “warm” but not burn-yourself hot.

Is the indicator stream flowing to show that the outboard is pumping water? What is the flow like? Have you tested the temp of the flow?

I’d be really disappointed if the marine shop you had it to didn’t pick up on an overheating issue like a water pump, blocked intake, mud in the head, thermostat, etc. Anything’s possible I suppose.

If you have water flow, I’d look at the air leak possibilities first. If there’s any doubt that this thing is pumping water, then look at that direction.

Grouse

With that old of a motor I would put my money on the fuil pick up tube is worn out on the inside of the tank. they will not last foever. hook up to a differant tank. see how it runs.