1985 Evinrude 175 Overheating/Fuel Issues

[guitman32]

First, greetings all...new member, first post after some minor lurking on the side.

Cliffnotes in BOLD

Back Story and facts:
Purchased a used 1976 21ft center console with a 1985 'Rude 175 VRO (removed - using premix). The boat has an internal 60 gal tank, not sure of tank condition. Also, it has an external fuel filter/separator. Electronics are bootleg to say the least, but fuel gauge and temperature buzzer work (along with lights and radio, etc but no other gauges).

First, did the usual service items (thanks again all for the guidance), as follows:

Water pump (new housing and impeller)
Lower case oil
Exhaust gasket
Spark plugs
Fuel Filter
Fuel separator filter
Thermostats (noticed significant deposits in passageways)
Thermostat Pressure (poppet?) valves (again, significant deposits; also rubber seals in decent condition)
Checked water pisser for blockages (found some old beehive)

Took her out for the first sea trial - Verdict: Overheat alarm at partial and open throttle:
**** valve showed ok stream, and ok stream out of the exhaust ports. Note they just looked OK, not what I would call a healthy stream. Pisser temp was warm, not hot. Tried pumping the ball wouldn't help the temp as the alarm still sounded at the same throttle points.

I immediately suspected it was either: Clogged water passageways/water deflectors in head, faulty thermostats (they are NEW, so doubtful but not unheard of), or maybe a fuel restriction.

Course of action: removed thermostats:
I KNOW I KNOW I KNOW ITS BAD FOR THE MOTOR.
I went this route just to verify it was a coolant flow issue NOT a fuel issue. Note that I completely removed the T-stats, did not leave the housing in (in hindsight I should have just removed the t-stat valve and left the housing - will replace once I resolve the issue).

Second sea trial. Verdict: Still giving an overheat alarm, but now alarm sounds at just under full WOT and starts with an intermittent beep and leads to solid beep if I stay on it:
Noticed much healthier stream at pisser and exhaust ports, and I could run her at anything but just under WOT to WOT for an extended time. This time however, when I pump the ball the alarm goes away at all throttle conditions.

Ok, so shes cooling better, but the problem hasnt been resolved. Seems to be a fuel issue at higher RPMs that is causing the issue as it stands. This makes me happy because hopefully I can resolve the fuel issue and replace the t-stats and still maintain proper temps. Although judging by the amount of deposits observed in the block there is probably still some cooling issue lurking in the shadows. Will try to run her in a tank with some salt treatment to see if I can clear things up.

Next steps: run on an external tank to verify if restriction is on motor side (ball, fuel pump, lines, carbs) or on tank side (tank, tank vent, lines, or restricted fuel separator)

Questions:
If the issue is on the tank side, what are my options to diagnose? The tank is under the console and a real PIA to get to. Not sure where the breather valve is, but Im hoping somewhere accessible so I can check for blockage. Also, the tank is of unknown age and condition.

If the issue is on the engine side, what are my options to diagnose? Do I check fuel pressure, check for gunked lines, or do I replace the pump ($406!) and/or inspect the carbs?

Am I missing anything?

Thanks for your input!

 

[jonesg]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

So many unknowns,
I would rebuild the carbs with carb kits, replumb the boat.
It might need a new tank too.

Get the service book if you don't have it yet,.
www.outboardbooks.com

 

[guitman32]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

So many unknowns,
I would rebuild the carbs with carb kits, replumb the boat.
It might need a new tank too.

Get the service book if you don't have it yet,.
www.outboardbooks.com

Thanks for the reply. Have the factory service manual; checked the fuel system troubleshooting section will use some of those techniques once I run on an external tank.

Is there any way to clean the tank if it is in fact the bottleneck? Can you work around a semi-dirty tank?

 

[jonesg]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Thanks for the reply. Have the factory service manual; checked the fuel system troubleshooting section will use some of those techniques once I run on an external tank.

Is there any way to clean the tank if it is in fact the bottleneck? Can you work around a semi-dirty tank?

The plumbing is 1976,the hoses are pre-E10 and not safe for today's fuel. The hose swells internally, it looks good but chokes the flow.
Tank is probably leaking beneath deck if original,
ThaTS why theres so many nylon tanks sold today.

My boat was mfgered in 1974, when I replaced all the hoses I noticed they were dated 1995, so 20 years is probably normal for fill hose, feed hoses should be replaced more often.

If pumping your bulb makes the alarm go away you have to suspect fuel delivery , external filters should be bypassed except for water seperator.
The external tank with new hose and bulb will tell.

 

[emdsapmgr]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

One other thing to check. That engine came from the factory with a fuel vacuum switch. It will sound a warning horn if the switch sees 7.0 inches of vacuum in the fuel system. This preset indicates that the engine could run lean due to high vacuum from the tank. Typically it will sound at the higher rpm's as the vacuum gets higher. You can check it by teeing into the fuel line with a vacuum gauge. The fact that the engine may be running cooler with the stats out may indicate some restrictions in the water system. It's easy to pull the water jacket covers off the heads (don't pull the heads) and have a look inside. The condition of the head water passages will give you an indication of the rest of the cooling passages in the powerhead.

 

[guitman32]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

The plumbing is 1976,the hoses are pre-E10 and not safe for today's fuel. The hose swells internally, it looks good but chokes the flow.
Tank is probably leaking beneath deck if original,
ThaTS why theres so many nylon tanks sold today.

My boat was mfgered in 1974, when I replaced all the hoses I noticed they were dated 1995, so 20 years is probably normal for fill hose, feed hoses should be replaced more often.

If pumping your bulb makes the alarm go away you have to suspect fuel delivery , external filters should be bypassed except for water seperator.
The external tank with new hose and bulb will tell.

Definitely my next step. If it does end up being something aft of the ball, then I'll have to consider replumbing as an option. I would probably use this as an excuse to change the tank, redo the console, electric and repaint.

In the short term however I might still consider draining the tank and attempting to clean. Have seen some services and options out there, not sure how effective they are though.

One other thing to check. That engine came from the factory with a fuel vacuum switch. It will sound a warning horn if the switch sees 7.0 inches of vacuum in the fuel system. This preset indicates that the engine could run lean due to high vacuum from the tank. Typically it will sound at the higher rpm's as the vacuum gets higher. You can check it by teeing into the fuel line with a vacuum gauge. The fact that the engine may be running cooler with the stats out may indicate some restrictions in the water system. It's easy to pull the water jacket covers off the heads (don't pull the heads) and have a look inside. The condition of the head water passages will give you an indication of the rest of the cooling passages in the powerhead.

I read that bit last night about the VRO system sounding the horn, but I have to say I'm not 100% it is connected. The buzzer wired into the system looks aftermarket, and has only one line connected to it, the other to the ignition. I inspected the wiring color, and it matches the wire on the temp sensor. Here is a pic of the buzzer (like I said, bootleg):

 

[guitman32]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Update: Ran her on an external tank.

The good, the alarm went away.

The bad, after a 15 minute run out the inlet, anchored for abt 30mins off the beach, upon restart a loud squeaky bad sounding, cringe inducing mechanical-ish noise and she bogged. Pisser was pissing while she was running.

Had to try and restart her to get home, changed batteries, verified fuel connections, no kinks, etc. She fired up, but had to give her throttle just to idle her. Had no power and wouldn't run right even while pumping the ball. If I gave her too much throttle, she would bog and shut down. Had to limp back through the inlet, could barely control her, and the motor cut once in the middle of the inlet...thats another story The whole time Im thinking it sounds like shes running on 5 cylinders. I got lucky.

Anchored at the sandbar to verify connections, etc. At this point she would fire and idle in neutral, but in gear nothing but enough thrust to barley control her. Limped back to the marina and pulled the cowl, noticed that the damn TIMING ADVANCE was disconnected AGAIN, even after new fittings. What an unreliable POS connecting system. Though at this point with the advance reconnected she idles fine and revs in neutral but the revs sound slightly unhealthy. Either way sounds like I did something bad.

Going to check compression, inspect plugs, inspect pistons/cyl and if things look questionable I'll pull the head and see whats up.

If the compression is OK did I get lucky? Could the timing advance have caused this issue? Could I have somehow fouled a plug? Any suggestions on where to go from here?

 

[emdsapmgr]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Your engine should have a 35 amp, vented flywheel. Check your flywheel magnets. It is possible one of the magnets came unglued from the flywheel.

 

[guitman32]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Your engine should have a 35 amp, vented flywheel. Check your flywheel magnets. It is possible one of the magnets came unglued from the flywheel.

Thanks for the reply. So that would explain the noise when I tried to start her the first time, correct? Also, would this explain why it felt like she was firing on only 5 cylinders? Also, I have read the flywheel removal procedure in the FSM, but do you know if it is exceedingly challenging on an engine this age?

 

[emdsapmgr]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Getting the flywheel nut off the crank is the easy part. An automotive flywheel holding tool is handy when you want to loosen/tighten that nut. You'll need a 3-legged wheel puller too. Once you get the puller mounted on the top of the FW and torqued tight-give the big puller screw head a single brisk rap with the hammer, it should pop right off.

 

[BigB9000]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

http://www.bigb9k.com/BRP/6603e/fw.html

 

[Rick-va3rzs]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Thanks for the site but it would help alot of we could make the photos bigger

 

[guitman32]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Your engine should have a 35 amp, vented flywheel. Check your flywheel magnets. It is possible one of the magnets came unglued from the flywheel.

Get this man a drink.

Magnets are cracked and loose, didn't even want to turn her over to check compression for fear of more damage. Stator exterior bits look ok on visual inspection, but wont know 100% until I get the flywheel off. Thanks for the solid advice!

Now I know what has been disconnecting the timing advance. Also I'm hoping this is what threw off the motor and was causing her to limp so severely, as opposed to the possibility of having done internal damage.

And back to the original issue, jonesg had it right. There must be a restriction in the fuel line before the ball, as running on the external tank solved the buzzer issue. Whether it was a temp or a vacuum buzzer, I do not yet know 100%.


BigB9000 thanks for the link. I have everything needed, and hopefully with air tools I wont have to worry about the rope/screwdriver trick.

 

[emdsapmgr]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Bombardier makes an epoxy glue kit for gluing those magnets back in place. Glue kits: 431929. If a magnet is damaged, they even sell them separately. Magnet replacements: 584304-this magnet kit includes the expoxy glue. Good luck!

 

[guitman32]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Bombardier makes an epoxy glue kit for gluing those magnets back in place. Glue kits: 431929. If a magnet is damaged, they even sell them separately. Magnet replacements: 584304-this magnet kit includes the expoxy glue. Good luck!

Thanks, looks like magnet repair is the way to go. Hopefully nothing else was damaged by the magnet particles. If I can get the flywheel off today Ill give you an update on the progress.

 

[guitman32]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Got the flywheel off. Pics of inspection as follows:

Flywheel & magnets: Two magnets in tact but completely loose, the third is in bits and pieces everywhere. Note that three magnets are still attached, but I will probably remove and re-epoxy just to be safe.

Top of stator: timer base and bearing looks to be in good shape

Side of stator: Notice the marred coil surfaces. Also, notice the damage on the top of the timing advance, surely what was knocking the connector out of the socket.

Front of stator from back of motor: Notice the damage to the one coil end there on the left, you can see that the magnets must have bent the little metal slits upward.

Another shot of the damage:

How does the stator look to you all? Is the damage minor, or will it effect how she runs? Worth replacing the stator (buku $$).

 

[guitman32]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Oh, and I completely forgot to mention, compression checked out the same as it did when I got the boat...needless to say I breathed a sigh of relief.

 

[jonesg]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Well ya can't run it like that so theres not much to lose by trying to straighten the coil end plates, then turn the flywheel by hand to see if it scrapes, dress with a file if needed to get clearance.

AKA beat to fit, paint it to match.

 

[guitman32]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Well ya can't run it like that so theres not much to lose by trying to straighten the coil end plates, then turn the flywheel by hand to see if it scrapes, dress with a file if needed to get clearance.

AKA beat to fit, paint it to match.

Thanks...I bent the end plates flat as best as I could, using pliers to compact them as I went. Came out pretty ok I would say. Those are the battery charging coils, no? I can't imagine the slight misalignment having a huge effect on that...?

Jumping back to the fuel issue, I was inspecting the fuel filter and noticed an uncomfortably tight looking loop in the fuel line from the inlet nipple to the filter...and a slight kink as a result of a tired line. Replaced that today...I think Im going to run on the internal tank again to see if this was the cause of the fuel restriction, and not a dirty tank/fouled anti siphon/clogged tank vent/old clogged lines/etc. I can honestly say that I did not route this line (someone else replaced the fuel filter when we were servicing), but either way I should have noticed earlier. Must Keep Eyes OPEN

Glued the flywheel magnets. I purchased two, re-used one of the loose magnets, and left the other three as-is. I was debating whether to replace, and I know the extra $75 would have been cheap insurance, but decided to leave them as-is. Hopefully that doesn't come back to bite me, but I know now to add to my checklist and inspect before and after every run...


Im letting them sit overnight as the instructions recommended 24hrs for the epoxy to cure. Tomorrow Ill have the flywheel back on, fire her up and see how she runs.

 

[guitman32]

Re: 1985 Evinrude 175 Overheating/Fuel Issues

Update: Put the flywheel back on, verified stator clearance (didnt have to file anything to fit, but deburred the edges of the damaged coil end plates to be on the safe side.

She started with a slight hesitation but then warmed up and idled nicely. The motor sounds, idles and revs like she did before the issue. If I shut her down and restart, she fires back up with a bark.

I also replaced the thermostat housings, but gutted the spring and valve - with the gunked up looking passageways until I remove the water cover and head I dont want to take any chances.

Sea trial tomorrow. I will run her on an external tank again to see how she fares. Thanks everyone for the help!