confused

[allen6634]

i have been fighting this issue since i bought my boat it is a 1983 sprint bass boat with a 88 spl. johnson on it what i don't under stand is that my motor will idel just fine when it is in neutral but when i put it in gear it will die also this motor runs great at full throttle and it also will run at or above the manufactures recommended rpm depending on my trim settings. can my prop be to big? thanks

 

[etracer68]

Re: confused

What rpm is it at idel, in neutral? It should be about 750rpm, and drop about 50rpm when put into gear. You may have some dirt in the idel circuts, in the carb. I would think you have a motor issue, more over a prop issue.

 

[allen6634]

Re: confused

What rpm is it at idel, in neutral? It should be about 750rpm, and drop about 50rpm when put into gear. You may have some dirt in the idel circuts, in the carb. I would think you have a motor issue, more over a prop issue.

the only way i have to get the rpm reading is the tach on my boat i just went out and checked the rpms out it is ideling at 2800 and i took the prop off just to see what it would do, with the prop off it idels great no issues .

 

[oldman570]

Re: confused

Still sounds like a idle circut in the carb needs to be cleaned up. That motor should idle as stated before at 650 to 750 with the motor in fwd gear. Have you tried to open the idle jet any to run the motor richer? Running a motor lean will cause trouble and could damage the motor. Adding pitch to the prop should lower the WOT RPM so the motor an setup of the boat will let you run within the correct RPM range under 5500 to 5700 RPM @ WOT. The only real way to test the setup is on the water with the tach and GPS if you need to know the real speed running. Have you used any Sea Foam in the gas mix yet or cleaned the carbs?
Oldman570

 

[steelespike]

Re: confused

Probably needs the idle speed adjusted and or the carbs rebuilt.
Please read "read this first " at the top of the prop forum.We need the wot rpm and gps speed.
Your tqch may be set wrong Or defective. If it is over revving the prop could be too small not too big
Prop size should be under the prop nut.

 

[allen6634]

Re: confused

as of yet i haven't done any thing to the boat i have only taken it out once and it would keep die every time id put it in gear and i thought i needed to figure this out before i break some thing .

Still sounds like a idle circut in the carb needs to be cleaned up. That motor should idle as stated before at 650 to 750 with the motor in fwd gear. Have you tried to open the idle jet any to run the motor richer? Running a motor lean will cause trouble and could damage the motor. Adding pitch to the prop should lower the WOT RPM so the motor an setup of the boat will let you run within the correct RPM range under 5500 to 5700 RPM @ WOT. The only real way to test the setup is on the water with the tach and GPS if you need to know the real speed running. Have you used any Sea Foam in the gas mix yet or cleaned the carbs?
Oldman570

 

[allen6634]

Re: confused

im sorry for not giving the prop info at first im new to boats hear is the prop info it iis a ss baker 13/1/2x22 i hope this helps the wot rpms depending on the trim settings is 5500 and the speed with 2 adults and one child is 50 mph

Probably needs the idle speed adjusted and or the carbs rebuilt.
Please read "read this first " at the top of the prop forum.We need the wot rpm and gps speed.
Your tqch may be set wrong Or defective. If it is over revving the prop could be too small not too big
Prop size should be under the prop nut.

 

[steelespike]

Re: confused

That must be a realy light fast boat and your numbers do make sense.
While it could be something else stalling when put in gear is a classic symptom of poor fuel delivery.
You should post your idle problem in the Evinrude/Johnson repair section.

 

[Frank Acampora]

Re: confused

Your tach MUST be way off. If the engine were idling at 2800 RPM the hull would be up on plane.

What many people do not realise is that higher pitched props increase the load on the engine even at idle and idle speed MUST be raised if it is below specifications.

An OMC 88spl with a 22 inch pitch prop should not over-rev at full throttle. so there again, it indicates an incorrectly reading tach.

However, 22 pitch is a lot to ask that engine to swing at idle. If the prop is not vented, you should first fix the tach or get a correctly reading one, then try to set idle speed to specs given in this post. THEN, you should experiment with venting the prop for better acceleration and possibly a more solid idle.

 

[allen6634]

Re: confused

i do understand that the pitch can raise or lower the speed like the rearend gears can on a car the one thing i don't know that ifthe prop pitch can cause the motor idel problems , im worried that the pitch may be putting to much of a load on my motor at idel .is there a clutch that could have failed?

Your tach MUST be way off. If the engine were idling at 2800 RPM the hull would be up on plane.

What many people do not realise is that higher pitched props increase the load on the engine even at idle and idle speed MUST be raised if it is below specifications.

An OMC 88spl with a 22 inch pitch prop should not over-rev at full throttle. so there again, it indicates an incorrectly reading tach.

However, 22 pitch is a lot to ask that engine to swing at idle. If the prop is not vented, you should first fix the tach or get a correctly reading one, then try to set idle speed to specs given in this post. THEN, you should experiment with venting the prop for better acceleration and possibly a more solid idle.

 

[Frank Acampora]

Re: confused

To rephrase what I said: A high pitched prop will load the engine more than a low pitched prop at idle. The extra load will cause idle speed in forward gear to drop below the quoted specification and more times than not, the engine will stall when put into forward gear. This will not harm the engine, only make life tough for the operator. The cure is to adjust the idle stop screw to raise the idle speed in gear up to manufacturers specs.

Without an accurately reading tach you are pretty much dead in the water. It is like trying to take a trip without knowing from where you are starting and not having a map. --- or having the wrong map.