81 115 evinrude lower unit question

[JST0771]

Quick question to help guide me in the right direction.

Can anything in the lower unit/gear case case the engine to bog down?

outboard has not run for over year maybe more. I just finished getting the power head running this weekend. It idles fine with muffs. On the lake when I get it gear it only got up to 3000 rpm at full throttle engine definitely sounded like it had more to give. The only thing I did to lower was replace water pump.

Did I miss something I should have done on the list unit knowing it has set for so long?

 

[interalian]

Oil change recently? Pumped from the bottom hole up to the vent (top) screw then cap?

 

[JST0771]

If you're referring to oil in the lower unit, I know nothing about it... yet. As for the powerhead, it's a 1981 2 stroke.

 

[flyingscott]

Do a compression test and definitely check the lower unit oil. Look for metal shavings.

 

[oldboat1]

Want to be sure there is oil in the l.u., assuming it was stored by someone else (motor new to you, maybe). Fresh fuel is an issue as well with a motor that has been stored. Test run it with a portable tank if it's on a boat with a built-in tank.

 

[racerone]

Compression test first.----Does spark jump a gap of 3/8" or more , yes or no ?------They all sound good on a hose even on 3 of 4 cylinders.

 

[JST0771]

Wish I could delete my reply to Interalian, that was a "Duh!" moment I regret.

I am picking up a compression tester at lunch, and check the condition of the oil since I have not since I bought it. Odds are I'll be emptying it and refilling it just to be on the safe side. Hopefully, I don't find metal chunks!

I won't get to the compression test until after work, sometime around 6 Central. I will let you know what I find.

Isn't this how its supposed to work? You buy an old boat and motor first, learn from your mistakes, (I've a made a few already,0) and then decide if owning another boat is worth it?

 

[JST0771]

I had spark with 1/2" gap on ignition tester for all 4.

I picked up an infrared thermometer to get an idea what and when it got to operating temp to do the compression test. Cylinders 2 and 4 got up to 105F while 1 and 3 only got to 85F. The sparkplugs reflected the difference. All gapped at .030 in.

Compression results were 91 across the board which seems low to me, but promising that they were all the same.

There is oil in the gear case, it looked clean enough to run for tests. But I will be replacing it. I do not know when it was last replaced.

 

[JST0771]

Doing some reading on the temp issue. Is it even possible to get the motor up to temp on a hose? I certainly can't do more than let it idle on a hose.

 

[oldboat1]

Warm up can be difficult on muffs (incoming water temp typically about 40F). In addition, the hose pressure is doing part of the work of the water pump and cooling system by providing pressure -- makes it hard to test the cooling system. Idling in a barrel is a little better in that the pump does the work and there is more normal back pressure. But there is a chance of overheating as the water in the barrel warms up (keep the hose running).

 

[JST0771]

Update. Took it to the lake again with fresh fuel. Ran it for about 15 minutes full throttle. Topped out at 3000 rpm. Never planed out, trim 2nd to the lowest. No power trim at the moment. Came back to shore for compression test. Engine temp on 2 and 4 was 146. Only 96 on 1 and 3. Compression was 100 to 98 across all cylinders.

I'm leaning toward a complete tear down unless someone has anything else I should check.

thanks for your help!