Confused About Bogging Down Motor??

[rkersh409]

I have an 1995 Evinrude 175HP motor that was bogging down on take off. But pushing in on the key would keep it from dying. So I cleaned my carbs and put in new carb kits. But that still didn't fix the problem. So I took it to an individual boat mechanic to see what the problem was.

After he looked at the motor he told me that the two top cylinders was 115 the two middle was 114 and the bottoms were 105 in compression. I know not the best but still within 10%. But he said my problem was the fact that the port side bank was over heating due to a bad thermostat. After 5 minutes on the water hose he said it got up to 184 degrees, but never set off the alarm. I know my alarm is working because I have grounded the temp switch just prior to taking it to him. How can I check to make sure the alarm works? So he opened my thermostat instead of replacing it. Also I just changed my water pump before taking it to him.

I know nothing about how boat motors work so could someone explain to me how a hot motor would cause the motor to bogg down on take off, but pushing in on the key to prime it would allow me to get up on plane. And also after getting hot the motor would not idle very well.

He also said my spark plugs was older then God and replaced them. Could bad plugs cause a motor to bogg and die when warmed up?

I just don't know if this really fixed my problem or not. What do y'all think?

 

[rickdb1boat]

Re: Confused About Bogging Down Motor??

I see it this way. If you have a clogged carb, it will cause certain cylinders to run hotter due to the lean mixture. I would go through the carbs again and soak them this time in cleaner. You can get a gallon at an auto parts store (NAPA). Then spray all the passages out with gumout. Don't forget to remove the jets for proper cleaning. Blow it out with compressed air and try it out after that. When you hit the primer, you are injecting fuel/oil directly into the cylinders and richening the mix manually. Also, make sure you have no air leaks in your fuel lines. When you have the carbs off, it would be a good time to inspect them all...Anything can affect performance, including old spark plugs. Replace the thermostat if he removed it with a new one..Have you tried out the motor since he worked on it??

 

[walleyehed]

Re: Confused About Bogging Down Motor??

If this is happening after it has ran a bit, it could be a tank vent plugged, or a fuel restriction else-where.
As Rick said, get a new T-stat in there...it's just as bad without one as it runs too cool. air getting into the line via a pin hole could possibly do it...so can a loose flap inside an old fuel line. your fuel pumps may not be putting out like they need to as well. It's very important both pumps are working as good as possible.

 

[rkersh409]

Re: Confused About Bogging Down Motor??

Thanks guys. No I havent ran it since the guy fixed it. I will be putting in new thermostats for sure.

My carbs are plastic so I cannot soak them in carb cleaner. But I did soak the jets in carb cleaner for two days then blew them and the passage ways out with an air compressor.

If it was an air leak in the fuel line wouldn't it do it all the time and not just when its warmed up?

I put in an air pump kit in my VRO last summer and that did not fix the problem. What is the other pump your speaking of?

I have two vents on my tank. I really dont think both of them would be clogged at the same time. But who knows stranger things has happened.

 

[rickdb1boat]

Re: Confused About Bogging Down Motor??

To rule out the fuel pump, pump the fuel primer bulb when it boggs and see if it helps....All of this may be for nothing until you verify that it still is running bad...

 

[ezeke]

Re: Confused About Bogging Down Motor??

"After 5 minutes on the water hose he said it got up to 184 degrees, but never set off the alarm."

Just for the record, the Temperature Switch' tan wire signal for the horn alarm is supposed to close at 197º F to 209º F. The Temperature Switch' White & Black wire to activate S.L.O.W. closes at 206º F to 218º F.

 

[ezeke]

Re: Confused About Bogging Down Motor??

ttt

 

[ezeke]

Re: Confused About Bogging Down Motor??

To keep a better watch on operating temperature, you may wish to add temperature guages to your setup. That would allow you to check if the engine is running too cold as well.

 

[rkersh409]

Re: Confused About Bogging Down Motor??

Yeah thanks ezeke I read that in my manual last night. I wonder why the guy didnt tell me that it wasent enough to set off the alarm.