90 HP Johnson 1985 - losing prime and alarm

[sweetmelissa]

I have a couple of problems and I'm looking for some help:

Problem #1:
At full throttle I start to lose power and I have to squeeze the primer bulb which is soft and it will pick right back up to normal speed running fine. It will stay hard for a little while and go soft again sometimes minutes later during the same test run. Any thoughts?

Problem #2:
I start the engine and within 3-5 minutes At low idle speed in nuetral and also when in gear at low speeds under 5 mph I will get an alarm that goes off ( 1 beep per sec. )This will continue until I rev the engine in nuetral or go faster than 10 mph in gear and then it stops. If I'm in gear going at a trolling speed and it sounds I can move the trottle and go faster and the beeps get faster ( 2-3 per second ) and then it stops beeping. The alarm has never sounded at speeds 10 mph or faster... Once the alarm goes sounds I can speed up and the beeps get quicker as I speed up. If I slow back down they get slower. But once I reach a certain speed around 9 - 12 mph they alarm stops..... I can run the engine at a slow a trolling speed and it will sound and then I can go fast and it will go off until I slow back down then within a few minutes of going slow again it will sound. Any thoughts?

Engine is a 1985 Johnson 90 hp.

Questions: What would make this alarm sound? Heat, Oil, water pump?

Here is the last work I had performed at the shop on June 24th, 2007:
1 - fuel filter 3/8" - $5.90
2 - KIT AY, F Pump&LMTR - $335
3 - KIT AY, Carb repair - $57.99 ( quanity 2 )
4 - Starter - $184
5 - Gasket V4 T-stat OM -
6 - Thomostat 130 Degr ( quanity 2 ) - $19.98
7 - Relief Valve Poppet - $2.19
8 - L77JC4 - Spark plug - $11.60 ( quanity 4 )
9 - Grommet OMC 321692 - $6.38 ( quanity 2 )

Mechanic Notes:
- Load tested battery it is O.K.
- Checked starter, it was drawing excessive amperage, replaced
- Checked fuel system, replaced several broken fuel clampsl
Test ran engine, excessive smoking due to several issues, replaced bad VRO pump, rebult carbs and repaired fuel leaks.
- Engine was running extremely cold, replaced thermostats.
- Engine runs much better now, shift and temp tested O.K.
- Engine is starting to have some internal wear.
Final Bill: $1297.57 ( ouch ) Engine ran great with no issues until August of 2009. I got 2 good summers and now I'm having the following issues mentioned above.

 

[sweetmelissa]

Re: 90 HP Johnson 1985 - losing prime and alarm

along with these two problems I just uncovered another:

My power trim will work one way and not the other.... Any thoughts where to start on this one

 

[jonesg]

Re: 90 HP Johnson 1985 - losing prime and alarm

Seriously get the service book, it has loads of info in it such as the alarms
www.outboardbooks.com

Was the water pump done?
Sounds like time for an impellor swap.

When the T/T fails to work, try the buttons on the cowl instead.
You might just need to disconnect the main harness plug and clean with elec spray cleaner.

There is no symptom in the manual for the buzzer you have but you can try disconnecting the temp sensor when its buzzing and see if it quits, then the vro sensor in order to isolate it. Temp sensor in in the cyl head inbetween sparkplugs, make sure the wire isn't touching sparkplug wires too.
Unpolug it and touch it to the head, the buzzer should sound with the ignition on, if so thats the correct wire. On mine its a brown wire.

The fuel bulb isn't supposed to remain hard once the engine starts running.

 

[emdsapmgr]

Re: 90 HP Johnson 1985 - losing prime and alarm

A constant buzzer is an overheat. Your warning signals are different-indicating problems with the oiling system. Perhaps the fuel/oil pump itself. I certanly would not be running the engine till I understood what the problem was. You may be risking running the engine without adequate oil lubrication. If you can get the engine to recover rpm's by constantly priming the fuel hose bulb, that is an indication of a weak fuel pump-even tho you just had it replaced. Have you checked for any fuel leaks in the hose system? It is also not unusual for the warning horn itself to be a problem. I know mine sets off an erroneous "no oil" signal when my oil tank gets low on oil. You can swap the trim soleniods (relays) in the box at the back of the powerhead. If the trim works the other way only-you have a bad solenoid. I'd replace them in pairs, keeping the good one as a spare.

 

[sweetmelissa]

Re: 90 HP Johnson 1985 - losing prime and alarm

I did a compression test and her is what I came up with: Could this be my problem? Would these reading make the boat run like I explained in prior postings...
#1 - 105 psi
#2 - 105 psi
#3 - 100 psi
#4 - 60 psi - Then I dropped a teaspoon of oil in and retested = got 85 psi
Would this cause me to constantly loose prime on the ball???? and make the boat run like it's starving for fuel.
I did search for leaks in the system and all the hose seemed good.... Water pump seems to be running good. I have a good steady powerful stream....

I will try and trouble shoot tomorrow more.... I fixed the trim problem. Thanks for the help.

 

[emdsapmgr]

Re: 90 HP Johnson 1985 - losing prime and alarm

The low compression on #4 is probably a condemning reading. It needs to be within 10% of the others to be in an acceptable range. Likely you have some issues with the piston/ring and cylinder walls. Pull the head and have a look. Possible a ring has broken (a common problem on these crossflows.) When you get low firing compression, you also have low crankcase compression-meaning that cyl can't suck fuel through the carb throat properly. Having said that, the low compression is unlikely the cause for either of your other problems. Probably the other way around. You will get higher (false) compression readings when you put oil in the cyl. The oil raises compression for a few rpm's. This oil will dissipate with the introduction of fuel, causing the compression to return to a "normal" reading.

 

[sweetmelissa]

Re: 90 HP Johnson 1985 - losing prime and alarm

Well I think I found the problem. Thanks for the help. I do have a couple more questions....

I ran the engine till the alarm sounded ( consistant beep per sec. ) I then unhooked the tan wires coming from the cylinders on both sides. This did not turn the alarm off. I then unhooked the oil sensor wire and this did not turn off the alarm. I wasn't sure if there was an alarm for the fuel pump so I traced the wires coming from that and unpluged the harness and the alarm stopped. Correct me if I'm wrong.... but I think I have a fuel pump problem. Which would explain why at full throttle I lose power and need to prime the ball.....So I believe the new one I just had put in on June 24th, 2007 has failed just after 10-20 or so runs on the lake. Is this normal for it to fail to quickly or am I missing another diagnostic test I could be doing?.... Does stuff get caught in the filter or something I can clean out or ... Any ideas what I can do to trouble shoot it further.... Do I buy another pump? I just had new hoses put on the boat so I don't think I have any air leaks anywhere. But I can trace them again.... Any idea's of how I can troubleshoot this further would be much appreciated.

 

[ezeke]

Re: 90 HP Johnson 1985 - losing prime and alarm

The driving pulse for the fuel pump comes from the #4 cylinder; without compression you don't get a pulse.

 

[sweetmelissa]

Re: 90 HP Johnson 1985 - losing prime and alarm

Can you explain a little better? What do you mean by pulse? When I said the cylinder #4 has low compression it's the one on the bottom right when facing the motor from the back.... So by replacing the fuel pump will fix nothing at all... Can you explain a little further... So this fuel pump may not be bad?

 

[ezeke]

Re: 90 HP Johnson 1985 - losing prime and alarm

All VRO and OMS fuel pumps are powered mechanically by the cyclical movement of one of the pistons which creates alternative vacuum and compression which moves a membrane inside the fuel pump. The V4 crossflow motors generally take that pulse from the #4 piston.

If you have concerns about the fuel pump, you should follow the test sequence found here or in your factory service manual: http://www.maxrules.com/graphics/vropics/VROflowchart.JPG

 

[sweetmelissa]

Re: 90 HP Johnson 1985 - losing prime and alarm

What would be a wiser choice? Replacing the engine with this kind of damage or repairing it. Would I need to rebuild the whole engine? Should I Rebuild a1985 Johnson 90 HP and fix this problem or should I be looking to find a new engine? Any idea on costs of fixing this? If I rebuild I imagine it would be $3k or more. Should I sink that much money into a engine this old? Part of me says yes... and part says no.
I would rebuild it and sink money into it if I could rest that it would not break down with other problems and start to nickle and dime me. However if it's going to cost thousands of dollars and not be reliable then I'd rather double the money upfront now and buy a new one. can anyone relate with my situation and give some feedback. Are rebuilds reliable?

 

[ezeke]

Re: 90 HP Johnson 1985 - losing prime and alarm

If you are still getting low compression readings, you may want to remove the cylinder head for the port side and examine the head gasket for possible damage. You can also take the bypass cover off so that you can examine that side of the #4 piston to see if the rings look OK. You will need new gaskets.

You may also want to replace the oil filter in the oil tank (which is almost never done).

Mark the oil tank and monitor how much oil you are using; it should amount to around 60:1 if your mechanic installed a new replacement fuel pump.

Check carefully for fuel and/or air leaks in your fuel system.

 

[emdsapmgr]

Re: How are you? superascxz

Re: How are you? superascxz

I'd follow ezeke's recommendation and pull the head. Could be something as simple as the head gasket. An engine with low compression will also suffer from poor suction, so that could be the fuel pump problem, as he also mentioned. Regarding the fuel pump, if purchased from a Bombardier dealer as an over-the-counter part, it should have a one year parts warranty from date of purchase. I have seen these OMS pumps replaced under factory warranty.