88HP 1988 Johnson

[bnhcomputing]

I am having prop problems. At full throttle the motor races and the boat stops as if shifted into the nutural position. One repair shop said they could find nothing wrong.

A second said I had "spun the prop." I put on a new prop and the problem is still there.

Any ideas?

 

[tashasdaddy]

Re: 88HP 1988 Johnson

you may have spun the new prop also. i have and 88 88. there are 2 metal hubs, lined with a rubber bushing take the prop off, draw a line with permantent marker across the metal parts. that the boat for a spin. if the lines are still line up. you either have a linkage. problem or a lower unit problem.

 

[bnhcomputing]

Re: 88HP 1988 Johnson

I went out and did the "mark the prop" thing right after reading the other posts here yesterday. Things are still lined up, so it's not the prop. In doing further research, I came across an article that talked about a damaged "dog clutch." Sounds like that may be the problem. I'll have to get the boat out of the water, and disassemble the lower unit to know for sure. If that is the problem, does anybody know if parts are available to fix this and from where?

 

[tashasdaddy]

Re: 88HP 1988 Johnson

parts diagram and list are available here, follow prompts. http://www.evinrude.com/en-US/Accessories/Literature/

get the OEM Johnson manual for your specific engine, before you tear into it. takes a certain procedure. outboardbooks.com

 

[bnhcomputing]

Re: 88HP 1988 Johnson

Had the entire lower unit gone through, NOTHING wrong. Three different shops tell me it's in PERFECT condition.

Take the boat out, and as soon as I go above 1/2 throttle, engine revs, boat stops, just as if shifted into neutral.

A NON boat guy said something about a damaged spline in the power head, and someone else suggested a linkage problem.

I'm just really stumped here, any more ideas?

 

[emdsapmgr]

Re: 88HP 1988 Johnson

A combination of an low-cup aluminum prop and a high transom mounting for the engine can cause this problem. Aluminum props are generally made to be fully submerged during running. If mounted too high, and the blade pierces the water, it can bring air bubbles back into the prop, causing ventilation like you mention. High cup, high rake stainless props don't suffer this problem as badly, as they can run with part of one blade out of the water and still have normal bite.

 

[Reggie08]

Re: 88HP 1988 Johnson

When the motor races then stops, is the shift lever back in the Neutral position or is it still in gear?

 

[bnhcomputing]

Re: 88HP 1988 Johnson

While underway, the motor will "race" like in neutral and the boat "drifts" to a stop, but the engine is still "racing" and still in gear (at full throttle position). Leading me to believe this is not a cavitation problem.

I have to shift back to neutral and then slowly move the throttle forward again. If I go beyond 1/2 to 3/4 of the way to full throttle, then engine revs, as if in neutral.

Can't verify if the prop is turning, as there is too much disturbance from the water pumping through the motor to see if the prop is turning.

What else can I tell you to help determine the problem?

 

[Reggie08]

Re: 88HP 1988 Johnson

Take this for what it's worth and understand I'm no expert, but I'm trying to brainstorm and help you trouble shoot. But this is something I personally would try first. Hopefully one of the experts on here can chime in and tell you if this will work or not.

Next time you're on the lake, put the motor in gear then remove the cowling. Reach down and find where the throttle/shift cable is connected at the motor and push the lever towards the back of the motor. This will ensure (hopefully) your motor is in gear (if you're not sure where that connection is, remove the cowling with the motor turned off then push the throttle up/forward like you're in the water and look for the cable that moves) Then take it and run the motor up to see if it "races" again. Does that make sense? If it runs fine, then your cable is either worn/stretched or out of adjustment. If it acts like it goes into neutral again, then remove the lower unit and make sure your shift rod is at the proper height (you'll need an OEM manual for that). If it's not at the right height, adjust accordingly (simply turn the shift rod in or out to obtain the proper height). If that still doesn't correct your problem then it could possibly be the clutch dog. But before you go throwing money at the motor, lets rule out some of the simpler things.

This is why I asked if your motor goes back into neutral or not. Even though your shift/control box shows it's still in gear, I'm wondering if your cables are out of adjustment that it's causing your lower unit to not go into gear completely and the higher rpm's and torque are actually causing your motor to pop back into neutral.

This may not be the case, but it's something I personally would look at and try to see if it fixes the problem.

 

[eli_lilly]

Re: 88HP 1988 Johnson

Can't verify if the prop is turning, as there is too much disturbance from the water pumping through the motor to see if the prop is turning.

I am sure that, with an 88hp outboard, there would be no confusing the prop disturbance at 3/5 throttle with the exhaust disturbance. You will absolutely know that the prop is turning as there should be about 20 feet of wash jetting out behind the boat.

-E