88 XP150 RPM problem

[dw200]

Wanted to get your thoughts on a problem with the old barge before I tear into it. The boat/motor has had very little maintenance in that past few years before it was given to me but with a fresh tank fuel it started and ran well a few weeks ago. No problems at all. However, the other day it started to lose power and drop to about 2000 RPM no matter the throttle position. it cleared up once and I got power back fo a while but it returned to the same problem shortly afterward. No stalling otherwise and it idled fine at the dock.

I'm thinking this is a fuel starvation/restriction issue. Partially clogged fuel filter??? Clogged pick-up tube??? Didn't think to check the fuel bulb at the time as I was beginning to worry about weather but due to age I may replace it anyway.

 

[jonesg]

Re: 88 XP150 RPM problem

Wanted to get your thoughts
The boat/motor has had very little maintenance in that past few years .

My thoughts would be to catch up on general maintenance,
take stock of the overall condition first rather than attacking the current problem because it may be a result of the lack of upkeep over time.

Thats to say, if you bring the maintenance up to date the liklyhood is the current problem will disappear. If not, at least you'll know what the problem isn't.

So I would start with a compression test, then a spark gap test, rebuild carbs with carb kits (not just spraying carb cleaner into carbs) ,then change lower gear oil with new seals on the drain screws, fuel filter if not already done, water pump and clean all grounds from battery to spark plug.

With all that done, if the problem persists it will indicate something ignition related.

I couldn't tell you the number of posts here show someone spending $500 for electrical parts only to find the real culprit was just a dirty carb.

 

[tashasdaddy]

Re: 88 XP150 RPM problem

my thought is it is overheating going into safe mod, which will not let it rev over 2000 rpms. also read the TOP SECRET FILE.

 

[dw200]

Re: 88 XP150 RPM problem

I am slowly working on the general maintenance items. Fuel filter and line are cheap so i am replacing them next. battery grounds are good. The lower unit oil looked good. that is the one thing that i know was worked on over the past few years.

I'll go the rest of the general stuff and see what happens. As far as overheating and "safe mode" I'll look into that as well.
Thanks

 

[ezeke]

Re: 88 XP150 RPM problem

I don't know if you have a safe mode on that engine, but overheating may still be the problem. Whatever is causing it, you are dropping a cylinder or two at speed and that's enough to go over the engine carefully. Be sure to include the thermostats in your checklist.

 

[dw200]

Re: 88 XP150 RPM problem

This seems to be an intermittent issue with this motor. One of the previous users said something about having to "idle in" a time or 2. Today, it appeared to work just fine. I'll keep checking..............

 

[dw200]

Re: 88 XP150 RPM problem

To get further opinions...when I was locating/pricing thermostats for the barge today, the local Evinrude guy wanted to immediately throw a water pump replacement at the engine without considering the thermostats first. All of you are much smarter about this than I am. Is he seeing the chance for a buck here or should I do it anyway?

I am not convinced that it is the pump. I would think that the issue would be constant if the pump were bad rather than intermittent (which it is) with a possible sticking thermostat or sensor going bad. But as I said before, there are much smarter people here than I.

 

[dw200]

Re: 88 XP150 RPM problem

...

 

[jonesg]

Re: 88 XP150 RPM problem

Do it all, change everything considered mainatinance, pump is one of the critical items, about 2 yrs is considered safe, after that its getting old fast.

Whilst the leg is down you can check/clear out water tubes.
Nothing wrong with changing the thermos too.
I'd do the lot and be done with it .

 

[dw200]

Re: 88 XP150 RPM problem

I probably will do all of that including the pump/impeller. It needs it. To say this barge was neglected would be an understatement. With that said, I put it out on the water today and the same RPM issue showed up after about 45 minutes of good hard running. Got back to the dock @ 2100 rpm max power and checked the cylinder heads and they were hot but not abnormally so. Pulled both overheat sensor wires with no improvement.

I am starting to go back to the fuel issue as the possible cause. The bulb was hard so if fuel is the cause it could be dirty carbs?????

 

[jonesg]

Re: 88 XP150 RPM problem

Rebuild carbs before you cook it beyond repair, water pump too.
Its doing the slow fry and going into SLOW on you.

 

[dw200]

Re: 88 XP150 RPM problem

I talked to one of the previous users and the motor got a water pump about 2 years ago. I don't think it is overheating as he said it seemes to do the same thing a time or 2 after the pump was replaced. I bypassed the overheat sensors last time out and it made no difference. Could bsomething be wrong in the iignition box?

Help...

 

[72SideWinderSS]

Re: 88 XP150 RPM problem

What Spark plugs are you using?
Try A set of (Q)L77JC4's
That corrected a similar problem on my 150.

 

[dw200]

Re: 88 XP150 RPM problem

Hadn't thought of that. I would have gotten around to that thru catching up on the neglected maintenance sooner or later but i will check tonight.

 

[72SideWinderSS]

Re: 88 XP150 RPM problem

I also agree with jonesg about cleaning the carbs and doing the rest of the neglected maintenance. Just get-er-done.

 

[dw200]

Re: 88 XP150 RPM problem

Found something interesting while checking the plugs last night. Wires were loose on 2 of the coils. One had the main spark wire loose and another had the control wire loose. Both snapped onto the terminals positively. I'll put it in the water later and see what happens.