Can't get above 2500 RPM and temp light comes on.

[beach]

Have a '61 Glasspar runabout with a '69 chrysler 105 hp. Boat, persons and gear about 2000 lbs (est). Cant get rpms over 2500 wot with a 13 1/4 X 19 Prop, michigan, aluminum. Motor is running on 87 octane with 50:1 oil ratio. Timing 32 btd. Heat light comes on after about 30 seconds running wot. Goes off after about 2 min idling.<br /><br />Are the two problems related some how?

 

[iRich]

Re: Can't get above 2500 RPM and temp light comes on.

when was the water pump last serviced?<br />Rich

 

[beach]

Re: Can't get above 2500 RPM and temp light comes on.

Pump was replaced this morning. Pumps lots of water. I even loosened thermostat cap a little and water wass squirting out even at wot. No thermostat installed right now. And yes vanes are installed correctly.

 

[scotiany]

Re: Can't get above 2500 RPM and temp light comes on.

Are you sure the timing is 38? That sounds way too high . Most of the Chryslers in my books are 28-32. The fact that it doesn't overheat at idle makes me even more suspicious of your timing.

 

[beach]

Re: Can't get above 2500 RPM and temp light comes on.

Yes, the timing is 32, I dont know why I thought it was 38. Can I double ck timing with a timing light? I timed it by the book with a 12v light off the coil.<br /><br />Could these problem be from not enough fuel, worn fuel pump or clogged carbs. Any way to ck. I was told the size and pitch of my prop should be fine for this boat and motor.

 

[rslatz]

Re: Can't get above 2500 RPM and temp light comes on.

Check fuel filters. Had the same problem last year in the Keys & it drove us crazy.The result was starving for gas from clogged filter.

 

[beach]

Re: Can't get above 2500 RPM and temp light comes on.

Fuel filter is brand new.

 

[rslatz]

Re: Can't get above 2500 RPM and temp light comes on.

Check your fuel ball & see it it sucking shut cutting down the gas.

 

[beach]

Re: Can't get above 2500 RPM and temp light comes on.

The primer bulb? It's new too and working properly. I'm going to rebuild both carbs and the fuel pump then run it and see if there is any change.

 

[sony2001]

Re: Can't get above 2500 RPM and temp light comes on.

I would say you have lost a cylinder. You can always try 28 degrees for a while.

 

[beach]

Re: Can't get above 2500 RPM and temp light comes on.

What do you mean by lost a cylinder?<br /><br />Compression is: #1 145, #2 140, #3 145, #4 145. All cylinder have good spark. I have removed a wire at a time with motor running and the spark travels 3/4" strong and blue to the plugs.

 

[sony2001]

Re: Can't get above 2500 RPM and temp light comes on.

Can you stove test your thermostat and put it back in.

 

[sony2001]

Re: Can't get above 2500 RPM and temp light comes on.

It must be the prop. On my 125 I use the 17" I have tried a 19 and 21. I'd say you need a 15" for a 105 hp.

 

[beach]

Re: Can't get above 2500 RPM and temp light comes on.

Do you think going from a 19 pitch to a 15 pitch will give me a 2000 rpm gain?

 

[scotiany]

Re: Can't get above 2500 RPM and temp light comes on.

I don't think the prop is your problem but, here's what I have for your engine.<br />PN P47-heavy load app. 13x12<br />PN P322-medium load 13x14<br />Have you taken your flywheel off yet and checked your point gap? It should be .009-.0011. It also says that your spark plug should be Champion L19V. I don't know how you check your timing. My '70 55hp requires a special tool which isn't available anymore. There is a timing procedure in the Seloc manual which comes pretty close. In my opinion ,if you get a manual get the Seloc.

 

[sony2001]

Re: Can't get above 2500 RPM and temp light comes on.

Sure you will get 2000 rpm more. Your staying on the back side of the power curve and I assume the boat won't plane.

 

[beach]

Re: Can't get above 2500 RPM and temp light comes on.

I'm willing to try a different size, pitch prop. I ran those numbers thru the search in the prop section and didnt get any matches. Do you have any other numbers that I can try to find a prop here.

 

[beach]

Re: Can't get above 2500 RPM and temp light comes on.

Does a newer 105 hp chrysler take the same prop. I found one searching for a 1972 motor but I don't know if they are the same.

 

[sony2001]

Re: Can't get above 2500 RPM and temp light comes on.

You have to go into the paper catalogs. They have a history. Note number of splines, thickness of hub, and if it is a flow-thru prop (doubt it). On line go to Michagen Prop (spelling?)